Why a black box isn't enough
A common mistake is to draw a black rectangle over text in a regular editor and send the file. It looks redacted, but the words are still underneath. Anyone can select them, copy them or find them with search. Sensitive details have leaked this way many times.
Redact PDF works differently. Each page where you draw a box is turned into an image at 200 dpi, with the boxes painted in solid black. The hidden text is deleted for real. There is nothing left under the black area to copy or recover.
The trade-off you should know about
Because redacted pages become images, they lose their selectable text. You can still read them, but you can't search or copy the rest of the text on those pages. Pages without boxes are not touched and keep their text as usual.
If you need the redacted pages to be searchable again, run the result through OCR PDF. It adds a text layer based on what is visible, and the blacked-out parts stay blank because there's nothing there to read. File size may also grow a little, since image pages usually weigh more than text pages. Compress PDF can help if you need a smaller file afterwards.
Redaction is permanent in the downloaded file. If you think you might need the full version later, keep the original in a safe place and only share the redacted copy.
Metadata is removed too
PDFs often carry hidden details like the document title, the author's name or the software used to create it. By default, Redact PDF removes this metadata. That helps when a file was made by a colleague or a law firm and you don't want those details traveling with it. You can turn this option off if you want to keep them.
Common redaction jobs
People redact bank statements before sending them to a landlord, hiding account numbers and unrelated transactions. Job seekers remove their home address from a resume before posting it publicly. HR and legal teams black out personal data from documents shared with third parties. Journalists and researchers hide names of sources.
Before you share the result, open it and check every page. Make sure each box covers the full word or number, including parts that appear in headers, footers or tables.
All of this happens in your browser. The original and the redacted PDF never leave your device, and nothing is stored on our side.