How to Redact a PDF — 3 Methods (Free, Adobe & Mac)

PDF is the most common format for sharing documents, which also makes it the most common format for accidental data leaks. Whether you are a lawyer sharing discovery documents, a doctor sharing patient records, or an HR manager sharing employee files, you need to permanently remove sensitive information before sending a PDF to anyone.

This guide covers three methods for redacting a PDF, from the easiest free option to professional desktop software. Along the way, we will explain what makes redaction permanent, what common mistakes to avoid, and how to handle situations where you also need to redact Word or Excel files.

Redactly is the only free online redaction tool that supports PDF, Word, and Excel. Whether you need to redact a single PDF or process multiple file formats, Redactly has you covered without any subscription fees.

Method 1: Redact a PDF Online for Free with Redactly

The fastest way to redact a PDF is online with Redactly. There is nothing to download or install, and the AI detects sensitive information automatically.

Method 2: Redact a PDF in Adobe Acrobat Pro

If you already have an Adobe Acrobat Pro subscription ($19.99/month), you can use its built-in redaction tool. Note that Adobe Acrobat Standard and the free Adobe Reader do not include this feature.

To redact in Adobe Acrobat Pro: open your PDF, go to Tools > Redact, mark the text or images you want to remove, then click Apply Redactions. Adobe removes the marked content permanently from the PDF content stream.

For a full step-by-step guide with screenshots, see how to redact in Adobe Acrobat.

Method 3: Redact a PDF on Mac (Without Adobe)

Mac users often wonder if Preview can redact PDFs. The short answer is: not securely.

Apple’s Preview app has markup tools that let you draw rectangles over text. But this is visual-only — the underlying text remains in the PDF and can be selected, copied, and pasted. This is the same problem as drawing black boxes in Word.

For secure redaction on a Mac, your options are:

• Use Redactly online — works in Safari, Chrome, or any browser on your Mac. No software installation needed.
• Use Adobe Acrobat Pro for Mac — the full redaction tool is available in the Mac version of Acrobat Pro.
• Python libraries (advanced) — tools like PyMuPDF can programmatically redact PDFs, but this requires technical expertise.

How to Permanently Redact a PDF (Unrecoverable)

Permanent redaction means the underlying text is completely removed from the PDF file. This is different from simply drawing a black shape on top of text, which is sometimes called “visual redaction.”

For true permanent redaction, the tool must:

• Remove text from the content stream — the actual text data is deleted from the PDF structure
• Flatten annotations — any markup or annotation layers are merged into the page
• Remove metadata — hidden information like author names and revision history
• Overwrite with a black mark — a visual indicator that text has been removed (optional but recommended)

To verify your redaction is permanent, open the redacted PDF and try to select the text where redactions were applied. If you can select or copy anything from those areas, the redaction is not complete. Also try searching for the original sensitive text using Ctrl+F or Cmd+F — if any results appear, the redaction failed.

Can You Unredact a PDF?

This is one of the most common questions about PDF redaction, and the answer depends entirely on how the redaction was applied.

If the redaction tool properly removed the text from the PDF content stream, then no, the redaction cannot be undone. The original text is gone. This is what happens with Adobe Acrobat Pro’s Apply Redactions feature and with Redactly’s redaction engine.

However, if someone simply drew black boxes over text using Preview, Google Docs, or a basic PDF editor, then yes, it can be unredacted. The boxes can be removed or the underlying text can be extracted. This is why using a proper redaction tool matters.

When choosing a redaction tool, always verify that it performs permanent removal, not just visual obfuscation. Read reviews, check the documentation, and test the output by attempting to extract text from redacted areas.

Also Need to Redact Word or Excel Files?

One of the biggest limitations of most PDF redaction tools is that they only work with PDFs. If someone sends you a Word document or Excel spreadsheet containing sensitive data, you cannot redact it with Adobe Acrobat or most other PDF redaction tools.

Redactly is different. In addition to PDF redaction, Redactly supports:

This multi-format support makes Redactly uniquely valuable for organizations that handle documents in various formats — which is virtually every organization.

Frequently Asked Questions