How to Hide Sensitive Information in a PDF

Before sharing a contract, medical record, invoice, or ID scan, you often need to hide certain details — a social security number, an account number, a signature, or a face in a photo. Simply drawing a black box over text in a PDF viewer is not enough: the underlying text or image is still there and can be recovered by selecting it, copying it, or opening the file in an editor. Real redaction removes that content permanently.

Our free online tool lets you draw redaction boxes directly on the page, choose how each area should be covered — solid black, solid white, blurred, or pixelated — and download a PDF where that content is gone for good. This is sometimes called "blacking out a PDF," "censoring a PDF," or "anonymizing a PDF," and it's the same underlying process as professional PDF redaction software.

Step 1 – Open the Redact PDF Tool

Go to our Redact PDF tool. You'll see a file upload area where you can click to select your PDF or drag and drop it onto the page.

Step 2 – Choose a Page

Once your PDF uploads, a preview of the first page appears. If your document has multiple pages, use the Previous and Next buttons to find the page containing the information you want to hide. You can add redaction boxes on as many pages as you need before applying anything — your boxes are kept as you move between pages.

Step 3 – Draw Redaction Boxes

Click and drag anywhere on the page preview to draw a box over the text, number, or image you want to hide. You can:

• Draw multiple boxes on the same page, or across different pages
• Move a box by dragging it to a new position
• Resize a box using the handle in its bottom-right corner
• Delete a box with the small × button on its corner, or the "Delete Selected" / "Clear All" toolbar buttons

Step 4 – Choose a Redaction Style

Pick how each area should be covered from the Style dropdown:

• ⬛ Black (default) — solid black fill. The most secure and common choice.
• ⬜ White — solid white fill. Useful for forms where a black box would look out of place.
• 🌫 Blur — heavily blurs the covered region instead of hiding it completely.
• 🔲 Pixelate — mosaics the covered region into large blocks, like a censored photo.

You can mix styles on the same page — for example, black out a paragraph of text while blurring a photo.

Step 5 – Apply and Download

When every area is positioned correctly, click Apply Redaction & Download. The tool removes the original content in each selected area — not just a shape drawn on top of it — and downloads the finished PDF automatically.

How It Works

For black and white redactions, the tool deletes the underlying text and image data inside the box and fills it with a solid color, so nothing can be copied, selected, or recovered from that area. For blur and pixelate styles, the tool renders just that small region of the page, applies the blur or pixelation effect, deletes the original content underneath, and places the altered image back in the same spot — so the visual effect is preserved while the original text or image is gone.

Privacy

Your PDF is processed on a secure server and automatically deleted within minutes. No account is required and nothing is stored permanently. Because redaction happens server-side and permanently removes the underlying content, the areas you cover cannot be recovered by anyone who receives the downloaded file.

Common Use Cases

Legal documents: Hide privileged information, client names, or case numbers before filing or sharing a document.

Financial records: Black out account numbers, routing numbers, or balances before sending statements to a third party.

Medical records: Remove patient names or identifiers to anonymize records for research or insurance purposes.

ID documents: Blur or black out a photo, signature, or ID number on a scanned passport, license, or ID card.

Contracts and NDAs: Hide confidential pricing or terms before sharing a redacted version publicly.

Frequently Asked Questions

Is the hidden information really removed, or just covered up?

It's really removed. The tool deletes the underlying text and image data inside each redaction box before filling it in, so the original content cannot be recovered by copying text, editing the PDF, or adjusting a blurred image.

What's the difference between blur/pixelate and black/white?

Black and white are solid fills — the most secure option because no trace of the original content remains visible. Blur and pixelate keep a visual hint of what was underneath (useful for photos or signatures) while still permanently deleting the original data.

Can I redact multiple pages in one pass?

Yes. Draw boxes on as many pages as you need — use Previous/Next to move between pages — then click "Apply Redaction & Download" once to process the entire document.

Will this reduce my PDF's file size?

Redaction isn't a compression tool, so size changes are usually minor. To shrink the file afterward, run it through our Compress PDF tool.

Is my document safe?

Yes. Files are processed on a secure server and deleted automatically within minutes. Your original upload is never modified — a new, redacted file is generated for download.

Can I undo a redaction after downloading?

No. Redaction is permanent by design — that's what makes it safe to share the result. If you need to change something, re-upload your original (unredacted) PDF and try again.

Related Tools

• Redact PDF – Hide sensitive information now
• Sign PDF – Add your signature
• Add Text to PDF – Add custom text like a date or note
• Crop PDF – Trim page margins
• Protect PDF – Password-protect the redacted file
• Unlock PDF – Remove a password from a PDF you own