How to Black Out or Redact Text in a PDF (Easy & Free Methods)
Ever needed to share a PDF but realized it contains private or sensitive information? Maybe it’s a confidential business report, a legal document, or just some personal details you’d rather keep hidden. The solution? Redaction—but beware!
Simply highlighting text in black won’t do the trick. Many people assume that covering text with a black box means it’s gone forever, but in reality, anyone can copy, paste, or even reveal the hidden text with a few simple tricks. True redaction ensures the text is permanently removed, making it impossible to recover.
So, how do you properly redact a PDF for free? Don’t worry—you don’t need fancy software or expensive tools. In this guide, you’ll discover:
✔ The best free tools to black out text in PDFs securely
✔ Step-by-step methods for Windows, Mac, and online platforms
✔ How to erase hidden data so redacted information stays unrecoverable
✔ Common redaction mistakes and how to avoid them
By the end of this guide, you’ll know exactly how to safely black out text in a PDF, keeping your sensitive information truly hidden. Let’s dive in!
What Is PDF Redaction & Why Does It Matter?
In today’s digital world, sharing PDFs is common, but sometimes, those documents contain sensitive information that shouldn’t be seen by just anyone. That’s where PDF redaction comes in. Redacting a document ensures that private details—whether legal, financial, or personal—are permanently erased and cannot be recovered.
What Does “Redaction” Mean?
Redaction is the process of removing or blacking out text in a PDF so that it is completely unreadable. Unlike basic editing, which just hides text behind a shape or color, true redaction ensures the content is permanently deleted from the document’s data. Once redacted, the information is gone forever and cannot be copied, pasted, or revealed using any tools.
Why Not Just Use a Black Box?
A common mistake people make is simply drawing a black rectangle over the text they want to hide. While this may look like redaction, the underlying text still exists in the document. Anyone can copy and paste the hidden text or even remove the black box to reveal the information underneath.
Proper redaction tools go beyond visual concealment. They delete the text at the data level, ensuring that even advanced recovery methods won’t bring it back.
When Should You Redact a PDF?
You should always redact a PDF when it contains confidential or private information that could pose a security risk if exposed. Here are some common scenarios:
✔ Legal documents – Court records, contracts, or attorney-client communications that contain sensitive case details.
✔ Financial information – Tax forms, credit card numbers, bank account details, or salary records.
✔ Personal details – Names, addresses, phone numbers, Social Security numbers, or medical records.
✔ Business secrets – Proprietary data, trade secrets, internal company reports, or classified government files.
Failing to properly redact a document could lead to data breaches, identity theft, or legal consequences.
Now that you understand why redaction is essential, let’s explore the best free ways to properly redact a PDF and keep your information safe!
How to Black Out Text in a PDF Using Adobe Acrobat
Redacting a PDF is essential when handling confidential information, whether it’s legal documents, business reports, or personal records. Adobe Acrobat Pro provides the most secure method for redacting PDFs, ensuring that sensitive text is permanently removed and cannot be recovered. Unlike free online tools that may only hide text visually, Adobe Acrobat Pro’s redaction feature erases text at the data level, making it impossible for anyone to retrieve the redacted content.
If you need a professional and foolproof redaction method, follow this step-by-step guide using Adobe Acrobat Pro.
Step-by-Step Guide: Redacting Text in Adobe Acrobat Pro
Step 1: Open Your PDF in Adobe Acrobat Pro
Launch Adobe Acrobat Pro on your computer and open the PDF document you want to redact. This method is available only in the Pro version, as the free version (Adobe Acrobat Reader) does not have redaction tools.
Step 2: Access the Redaction Tool
Click on “Tools” in the top navigation bar and select “Redact” from the list of available options. This will open the redaction toolbar, allowing you to select and permanently remove text.
Step 3: Mark the Text for Redaction
Click “Mark for Redaction” and then use your cursor to highlight the text you want to remove. You can select words, sentences, or entire paragraphs by clicking and dragging over the desired area. The marked text will appear with a black or red overlay, depending on your settings.
Step 4: Apply Redactions to Permanently Remove Text
Once you’ve marked all the necessary sections, click “Apply Redactions”. A warning will appear, notifying you that redactions are permanent and cannot be undone. Confirm your decision, and the selected text will be completely erased from the document.
Step 5: Save Your Redacted PDF
After applying redactions, save the document by clicking File > Save As. This ensures that your original file remains unchanged, and you have a redacted version to share safely.
Pros & Cons of Using Adobe Acrobat Pro for Redaction
✅ Most secure method—completely removes sensitive text from the document’s metadata
✅ Easy to use—intuitive redaction tool with precise selection options
✅ Works offline—no need to upload sensitive documents to the internet
❌ Paid software—requires an Adobe Acrobat Pro subscription, which may not be ideal for occasional users
If you’re looking for a completely secure way to redact PDFs, Adobe Acrobat Pro is the best option. However, if you don’t have a paid subscription, you can use free online tools. Let’s explore how to redact a PDF for free using DocHub and Pdf4sure.
Redact a PDF for Free Online (DocHub & Pdf4sure)
If you don’t have Adobe Acrobat Pro, there are several free online tools that allow you to black out text in a PDF. However, not all free tools truly remove the text—they may only hide it, which means someone could potentially recover the information. That’s why it’s important to choose the right method.
Here are two free and easy online methods to redact PDFs:
Method 1: Using DocHub (Free & Easy)
DocHub is a simple online tool that allows you to redact PDFs by adding black boxes over sensitive text and then flattening the file to lock in the redaction.
Step-by-Step Guide for DocHub:
1. Go to dochub.com and sign in (free accounts available).
2. Upload your PDF by dragging and dropping the file into the editor.
3. Select the Rectangle Tool from the toolbar.
4. Cover the sensitive text with a black box.
5. Click “Flatten”—this locks the black box in place and prevents anyone from moving or deleting it.
6. Click “Download” to save your fully redacted PDF.
✅ Pros:
✔ Free to use for basic redactions
✔ Simple drag-and-drop interface
✔ Allows you to edit and annotate PDFs
❌ Cons:
✖ Black boxes may not fully erase the text underneath
✖ Requires an internet connection
Method 2: Using Pdf4sure (Free & Online)
Pdf4sure is another free tool that allows you to edit and redact PDFs directly from your browser. While it’s useful for quick redactions, it doesn’t fully erase text at the data level, so it’s less secure than Adobe Acrobat Pro.
Step-by-Step Guide for Pdf4sure:
1. Visit Pdf4sure.com and select “Edit PDF.”
2. Upload your PDF by dragging it into the editor.
3. Choose the Rectangle Tool and draw black boxes over the text you want to redact.
4. Click “Apply” to save changes.
5. Download your redacted PDF to your device.
✅ Pros:
✔ 100% free for occasional users
✔ No software installation needed
✔ Quick and easy for simple redactions
❌ Cons:
✖ Doesn’t permanently erase underlying text—only hides it
✖ Limited free use before requiring a paid upgrade
Which Redaction Method Should You Use?
For maximum security, Adobe Acrobat Pro is the best option because it completely removes sensitive text from the document. If you need to redact highly confidential or legal documents, this is the safest choice.
If you’re looking for a free solution, DocHub is a better option than Pdf4sure because it allows you to flatten the document, making redactions more permanent. However, if security is a priority, avoid using free tools for highly sensitive information.
For those who need a balance between security and affordability, offline alternatives like Foxit PDF Editor or LibreOffice Draw can offer more reliable redaction than free online tools.
Now that you know how to black out text in a PDF, let’s explore common redaction mistakes to avoid to ensure your sensitive data remains protected.
How to Redact a PDF on Windows for Free (Using Microsoft Word)
If you don’t have Adobe Acrobat Pro and need a free way to redact text in a PDF, you can use Microsoft Word. While Word doesn’t have a built-in redaction tool, it allows you to convert PDFs into editable documents, where you can manually black out text.
This method is simple and works well for basic redactions, but it does not permanently erase text from the document’s metadata. If security is a concern, consider using Adobe Acrobat Pro or another specialized redaction tool.
Step-by-Step Guide: Redacting a PDF with Microsoft Word
Step 1: Open the PDF in Microsoft Word
- Open Microsoft Word and click File > Open.
- Select the PDF file you want to redact.
- Word will display a message stating it will convert the PDF into an editable format. Click OK to proceed.
Step 2: Select the Text You Want to Redact
- Once the PDF is converted into an editable Word document, scroll to the section you need to redact.
- Highlight the sensitive text by clicking and dragging over it.
Step 3: Change the Font Color to Black
- After selecting the text, go to the Font Color option in the toolbar.
- Select black to obscure the text.
Step 4: Use the Highlight Tool for Additional Coverage
- To ensure the text is completely hidden, use the Highlight tool (located in the text formatting options).
- Choose black as the highlight color and apply it over the redacted text.
Step 5: Convert the Document Back to PDF
- Once you have blacked out the sensitive information, save the document as a PDF.
- Click File > Save As and choose PDF as the file format.
Step 6: Save and Share Your Redacted PDF
- Make sure to review the document before sharing.
- If security is important, consider flattening the document or converting it to an image-based PDF.
Pros & Cons of Redacting a PDF with Microsoft Word
✅ Free & easy—no need for additional software
✅ Works with Microsoft Word, which many people already have
✅ Good for simple redactions like removing personal details
❌ Text may still be recoverable—not a true redaction method
❌ Editable format—someone could remove the blacked-out text
❌ Formatting changes—converted PDFs may not look exactly like the original
When to Use This Method
Using Microsoft Word for redaction is best for casual use, such as hiding basic personal information before sharing a document. However, for confidential or legal documents, this method is not secure. The hidden text can still be retrieved, making it unsuitable for sensitive files.
For permanent redaction, consider using Mac Preview (for Mac users) or dedicated redaction tools. Let’s explore a better alternative for Mac users next!
Redact a PDF on Mac Using Preview (Built-in Tool)
Mac users don’t need to install extra software to redact a PDF—Apple’s built-in Preview app allows you to black out sensitive text quickly. This method works well for basic redactions, but it doesn’t always permanently erase the hidden text underneath. If security is a concern, you may need a more advanced tool like Adobe Acrobat Pro.
Step-by-Step Guide: Redacting a PDF with Preview
Step 1: Open the PDF in Preview
- Locate the PDF file on your Mac.
- Double-click to open it in Preview (the default Mac PDF viewer).
- If it opens in another program, right-click the file, choose Open With, and select Preview.
Step 2: Select the Rectangle Annotation Tool
- In the menu bar, click Tools > Annotate > Rectangle.
- This tool allows you to place a black rectangle over the text you want to redact.
Step 3: Black Out the Sensitive Text
- Click and drag to draw a black rectangle over the text you want to hide.
- To make the rectangle black:
- Click the color picker in the toolbar.
- Select black as the fill color.
- Set the border color to none (or also black).
Step 4: Save as a Flattened PDF
- Go to File > Export as PDF.
- Before saving, ensure the PDF is flattened—this prevents someone from simply removing the black box and revealing the hidden text.
Step 5: Review and Save the Final Redacted PDF
- Open the newly saved PDF and try to select the text underneath the black box.
- If the text is still selectable, the redaction is not secure—you may need an advanced tool to remove the text permanently.
Pros & Cons of Redacting a PDF with Preview
✅ Built-in tool—no extra software needed
✅ Quick & easy for basic redactions
✅ Works offline without an internet connection
❌ May not fully remove text underneath—text can still exist in the document’s metadata
❌ Not ideal for sensitive or legal documents
When to Use This Method
Using Preview for redaction is great for casual use, such as hiding personal information before sharing a document. However, for highly sensitive or legal documents, this method is not foolproof.
For better security, try Adobe Acrobat Pro or a PDF editing tool that fully removes the text, ensuring it cannot be recovered. Let’s look at a more secure method next!
Permanently Remove Hidden Text from a PDF (Forensic Proof)
Blacking out text in a PDF may look secure, but in many cases, the hidden information still exists in the document’s metadata or editable layers. This means that someone with the right tools can uncover redacted details—especially in legal, financial, or classified documents.
To permanently erase all sensitive information and make your redaction forensic-proof, follow these three essential steps.
Step-by-Step Guide: Maximum Security Redaction
Step 1: Redact the Text Properly
Before removing hidden data, you need to black out the text correctly using a trusted tool. Here are secure options:
✔ Adobe Acrobat Pro – Use the Redaction Tool for secure removal.
✔ DocHub (Online) – Add a black box and flatten the PDF to lock edits.
✔ Microsoft Word – Convert to Word, black out text, then save as a PDF.
⚠ Warning: Simply placing a black box over text in a standard PDF editor is not enough—the original text may still be selectable and recoverable.
Step 2: Flatten the PDF (Remove Editable Layers)
Flattening a PDF merges all layers into a single, uneditable document, ensuring that hidden text cannot be copied or removed.
How to Flatten a PDF in Different Tools:
✔ Adobe Acrobat Pro:
- Click Print > Print to PDF
- Select “Save as Image” (this converts all content into non-editable text).
✔ Pdf4sure (Free & Online):
- Upload your PDF to Pdf4sure.com.
- Choose “Flatten” under the Edit menu.
- Download your fully flattened document.
✔ Microsoft Print to PDF (Windows Users):
- Open the redacted PDF in any viewer.
- Click File > Print and select Microsoft Print to PDF.
This creates a new PDF with all text locked into place.
⚠ Important: Flattening makes the PDF uneditable, so double-check for errors before saving.
Step 3: Remove Hidden Metadata
Even after flattening, PDFs store metadata (hidden information like author names, previous edits, or document history) that could still expose redacted content.
How to Remove Metadata from a PDF:
✔ Adobe Acrobat Pro:
- Click Tools > Redact > Sanitize Document.
- This removes hidden text, metadata, and embedded data.
✔ PDF Metadata Remover (Free Tool):
- Use a free metadata removal tool like PDF Redactor or PDF Metadata Remover.
- Upload your document and wipe all metadata before saving.
✔ Mac Preview (Alternative for Mac Users):
- Open the file in Preview.
- Click File > Export and select Reduce File Size to strip hidden data.
Pros & Cons of Permanent Redaction
✅ Ensures no text can be recovered
✅ Best for legal, financial, and classified documents
✅ Removes all metadata and hidden layers
❌ Requires extra steps compared to simple redaction
❌ Flattening makes the PDF uneditable—double-check everything before saving
Why Permanent Redaction Matters
If you’re handling legal, corporate, or personal information that must stay confidential, taking extra steps to fully erase hidden text is essential. Basic blackouts may seem effective, but without flattening and metadata removal, your data is still at risk.
By using the right tools—like Adobe Acrobat Pro, Pdf4sure, and metadata removers—you can guarantee that your redacted PDF is truly secure and unrecoverable.
Need an extra layer of security? Consider converting your redacted PDF into an image-based format before sharing it. Now, you’re ready to redact PDFs like a pro!
Common PDF Redaction Mistakes & How to Avoid Them
Redacting a PDF might seem simple, but many people make critical mistakes that leave hidden text accessible. Here are the most common errors and how to ensure your redactions are truly secure.
Mistake 1: Only Using a Black Highlight
A common misconception is that using a black highlight or rectangle over text makes it unreadable. While this may hide the text visually, the underlying data still exists in the document and can be copied or extracted.
✅ Fix: Use proper redaction tools like Adobe Acrobat Pro or DocHub that permanently remove the text, not just cover it.
Mistake 2: Forgetting to Flatten the PDF
If you add a black box over text without flattening the PDF, someone can remove the box or copy and paste the hidden text. This is a major security risk.
✅ Fix: After redacting, always flatten the PDF to merge all layers. You can do this by:
Printing to PDF (File > Print > Save as PDF)
Using the Flatten option in Pdf4sure or Adobe Acrobat
Mistake 3: Leaving Metadata in the File
Even after blacking out and flattening text, hidden metadata may still contain document history, author details, or previous versions with redacted information.
✅ Fix: Always remove metadata before sharing a redacted file. You can do this by:
Using Adobe Acrobat Pro → Click Tools > Redact > Sanitize Document
Using a PDF metadata remover (free tools available online)
Secure PDF Redaction Made Easy
Properly redacting a PDF ensures sensitive information is permanently removed, preventing unauthorized access. Depending on your needs, you can choose from these methods:
✔ Adobe Acrobat Pro – The most secure, but requires a paid version.
✔ Online tools (DocHub, Pdf4sure) – Free and easy, but may not fully erase text.
✔ Microsoft Word & Mac Preview – Simple alternatives, but require extra steps for full security.
✔ Flattening & Metadata Removal – The final step to ensure redacted text cannot be recovered.
By following these best practices, you can safely redact any PDF before sharing it. Try these tools today and protect your sensitive information!