How to redact a signed PDF without breaking it

Redacting a signed PDF is a little different, because the signature exists to prove the file hasn't changed, and redaction changes it by design. Once you understand what the signature is protecting, the rest is straightforward.

Two kinds of signature

A digital signature locks the document cryptographically. Redact anything and that signature becomes invalid, which is correct: it was protecting the original, and your redacted copy is a new document. A visible signature image, like a scanned or drawn one, is just content on the page, and you can redact it like anything else if it needs to go.

So redacting a signed PDF really means making a new, redacted copy. If that copy needs to be signed too, you sign it again afterward.

The steps

1. Open the file in a browser redactor. It stays on your device.
2. Box what needs removing, and decide whether the signature image itself should go.
3. Apply. The content inside each box is removed and the page is flattened, so nothing can be recovered.
4. Download the redacted copy. If there was a digital signature, expect it to read as invalid on this new copy. That's normal.
5. Re-sign the copy if your workflow needs a valid signature.

Then confirm: select all the text, copy, paste, and check that nothing you redacted survived. Why this check matters.

Redact a signed PDF for free.