How to Redact a PDF on Mac (Actually Remove Text)

Drawing a black rectangle over a name does not remove the name — anyone can copy the "hidden" text right out from under the box, and it happens in leaked documents constantly. Preview has a real Redact tool that deletes the content itself. Here's how to use it, and how to prove the redaction worked.

Why a black box isn't redaction

A PDF stores its text as text, and annotations — rectangles, highlighter strokes, scribbles — as a separate layer on top. Cover a phone number with a black shape and the number is still in the file: select the area and copy, and it pastes out in full. Search finds it. Screen readers speak it. The only safe approach is a tool that removes the content, and Preview has had one since macOS 11, so it's built into Ventura, Sonoma, and Sequoia alike.

Redact with Preview

1. Open the PDF in Preview and choose File → Duplicate (then save the copy). Redaction is permanent, and you'll usually want an intact original for yourself.
2. Choose Tools → Redact. Preview shows a warning that anything you mark will be permanently removed when you save — click OK.
3. Mark the sensitive content: select text with the cursor to redact exact words, or drag a rectangle to redact a region, which also catches images, signatures, and anything else inside the box.
4. Each marked area turns solid black immediately. Keep marking until you've covered everything on every page.
5. Save (Cmd + S) and close. On save, Preview deletes the underlying text and image data — the black boxes are now covering nothing.

There is no undo after the save. If you redacted the wrong thing, go back to the original and start over — which is exactly why step one is a duplicate.

Verify the redaction worked

Trust, then verify — it takes thirty seconds:

• Search the file (Cmd + F) for a redacted word. It should return no results.
• Select-all and copy (Cmd + A, Cmd + C) on a redacted page, paste into TextEdit, and confirm the sensitive text isn't in the dump.
• Check the metadata with Tools → Show Inspector (Cmd + I) — the title, author, and keyword fields sometimes carry names the pages don't.

What Redact doesn't cover

Redaction removes what you mark — nothing else. A few things still deserve a look before the file leaves your Mac. The filename itself can leak (Offer_Letter_JSmith_Final.pdf). Inspector metadata survives redaction unless the creating app is used to strip it. And if the sensitive text repeats — a name in a header on all 40 pages — you must mark every instance; Preview has no find-and-redact-all, so run a search first and walk the hits. For scanned PDFs the text lives in an invisible OCR layer, and rectangle redaction removes that layer along with the image beneath it, so the same drag works there too.

Redacting images is a different job

A JPG or PNG has no hidden text layer — the pixels are the content — so for images the black-box approach actually works, with one condition: the box must be flattened into the image, not floating above it. In Preview, draw a filled black rectangle over the sensitive area with the shapes tool, then File → Export to a new JPEG or PNG. The export renders the shape into the pixels, and the covered content is gone for good. What you must not do is share the file in a format that preserves editable annotation layers — and remember that macOS reads text out of images too, so verify with Live Text: if you can still select the "hidden" text in the exported file, the box didn't flatten.

Sharing the file after redaction

If the PDF also needs access control — not just removed content — add an open password on export. See how to password protect a PDF on Mac for the difference between encryption and permissions.