Black Out Text in a PDF

Only when the page is rebuilt. Drawing a rectangle over text leaves the words underneath, and anyone can select, copy or extract them. This tool re-draws the whole page as an image with the areas filled in, so the original text no longer exists in the file.

Only the pages that actually contain a match. Pages without one keep their original vector content, so their text stays selectable and the file stays as small as it can be.

No. A re-drawn page is an image, so its text layer is gone. If the rest of the document needs to stay searchable, run OCR PDF on the result afterwards — a solid black area cannot be read back, so the hidden words stay hidden.

No. Matching ignores capitals, so a single entry covers "John Smith", "JOHN SMITH" and "john smith" alike.

Not as one block. Listing the individual words, or a distinctive phrase that appears in it, is the practical route. For a large region, cover it in a PDF editor instead.

Matching is a straight text search. A short entry such as "Ann" will also hit "Announcement". Enter a longer, more distinctive phrase to narrow it down.

Not directly. A scan has no text to search, so nothing can be matched. Run OCR PDF first to add a text layer, then redact the searchable copy.

No. The document is analysed and rebuilt entirely in your browser, and the result is created on your own device.

Not in the output — that is the whole point. The original file on your computer is never modified, so keep it if you might still need the untouched version.