How to redact a PDF: permanently remove information (the right way)

Before sending a payslip to a letting agent, a court decision to a third party, a medical file to an insurer or a document to a journalist, you often need to hide some information: national insurance or social security number, bank details, home address, people's names. This is called redacting (or anonymising) a document.

But beware: the most intuitive method, drawing a black rectangle over the text, often hides nothing at all. This guide explains why, how to redact a PDF properly, and which data to remove.

Why a black box is not enough

In a PDF, a rectangle drawn over text does not erase that text: it covers it visually. The original text stays in the file. Anyone can then:

• select and copy the text under the rectangle and paste it elsewhere;
• search (Ctrl+F) and find the "hidden" word;
• move or delete the rectangle with PDF editing software.

Several well-known cases of badly redacted official documents have exposed confidential information exactly this way. Real redaction must remove the information from the file, not just hide it on screen.

Redact a PDF properly, step by step

1. Open Redact PDF and drop your document.
2. Draw rectangles over everything you want to remove: a word, a line, a block, a photo, a signature.
3. Check every page: sensitive information often appears in several places (header, footer, appendices).
4. Download the redacted document.

Redacted areas are permanently erased in the downloaded file: the affected pages are rebuilt as images, so the original text no longer exists, neither under the box nor anywhere else on the page. As a result, the rest of the text on those pages can no longer be selected. Other pages stay unchanged.

Redaction is a Premium tool.

Check every occurrence manually

In a long document, it is easy to miss an occurrence. Review each page and check especially for:

• names;
• emails and phone numbers;
• bank details (IBAN);
• addresses;
• ID numbers;
• dates of birth.

You choose which areas to remove before exporting. This version does not offer automatic personal data detection or OCR: check the whole document yourself.

Manual redaction with rectangles also works on scanned pages, without recognising their text.

Which information should you redact?

Document	Information often worth hiding
Payslip	Social security / national insurance number, detailed pay as needed
Bank statement	Full IBAN or account number, unrelated transactions
Tax document	Tax reference numbers
ID document	Document number, photo depending on the use
Court decision, report	Names and addresses of the people involved
Medical file	Anything the recipient does not strictly need

The right reflex, recommended by the GDPR and good privacy practice everywhere: only share the data the recipient strictly needs (data minimisation).

Checks before you send

After redacting, open the downloaded file and:

1. try to select the text under the black areas: nothing should copy;
2. search (Ctrl+F) for a redacted word: it should not be found;
3. check every page, including appendices and footers;
4. check the file name, which can also contain a name or reference.

Frequently asked questions

Can redaction be undone?

No, that is the whole point: the information is removed from the downloaded file. Keep the original somewhere safe if you need it.

Can I redact a scanned document?

Yes, manual redaction works on scanned pages. Draw the areas to remove and check every page before sharing.

How is this different from the editor's Erase tool?

In the PDF editor, the Erase tool also really removes erased content from the final file. The redaction tool is dedicated to this job, with black boxes.

Is redaction enough to anonymise under the GDPR?

Not always: a document can still identify someone through cross-referencing (job title, place, date). For full anonymisation, consider every piece of information that could identify a person.