How to redact a PDF on a Mac, iPhone, or iPad
Preview on a Mac can truly redact text. Markup on an iPhone or iPad cannot. Here is what each tool removes, and how to check the result before you send it.
Preview on a Mac has a real redaction tool built in. It removes the text you select, not just its look. Markup on an iPhone or iPad does not have that tool: it only draws on top of the page. This guide walks through both, plus a short test to run before you send any file.
Does Preview on a Mac really redact text?
Preview has included a tool called Redaction Selection for years, and Apple documents it across every version of its guide, from macOS Monterey to the current release. Apple's own description is short: select text to remove it from view. The tool works only on text you can select, so it does nothing on a scanned page, since a scan is really a picture.
- Open the PDF in Preview, show the Markup toolbar, then choose the Redaction Selection tool.
- Drag over each block of text you want gone. Preview covers it with a black bar right away.
- Check every page for footers, footnotes, tables, and stamps, not only the main paragraphs.
- Close the document. Apple says the redaction becomes permanent once you do.
- Reopen the file and run the checks near the end of this guide before you send it.
What does Markup on an iPhone or iPad do?
Markup is Apple's drawing tool for screenshots, photos, and PDFs, built into Mail, Messages, Files, and Photos. Apple's own guide lists a pen, a highlighter, a pencil, shapes, text, a signature, and a magnifying loupe. Nothing on that list removes content. Every tool in Markup draws on top of the page, and Apple's guide never mentions redaction on iPhone or iPad.
Take Jane Example. She scans a lease with her iPhone, which saves it as a PDF, then opens it in Files and draws a black rectangle over her bank details with Markup before sending it to a roommate. The rectangle is a shape sitting on its own layer above the scanned page. Anyone who opens the file in another app can select that shape and move it, the same way a highlighter mark in Word can be lifted off a hidden word.
Why doesn't exporting or printing fix it?
On a Mac, Apple's Preview guide notes that File, Print, Save as PDF flattens annotations so that they can't be edited. That only locks the shape in place. It says nothing about deleting what sits underneath it. The UK's Information Commissioner's Office, or ICO, tested this exact idea with a highlighter in Word and a plain export to PDF:
Even using a 'Save as PDF' or 'Print as PDF' function is unlikely to provide effective redaction because the PDF file format can support formatting marks such as the highlighter.
Which built-in tool actually removes text?
Here is how the tools compare, device by device, based on what each maker documents.
| Device | Built-in tool | Removes text? | What to do instead |
|---|---|---|---|
| Mac | Preview, Redaction Selection | Yes, once you close the file, per Apple | Close, reopen, and run the checks below |
| Mac | Preview, Shapes, Sketch, Draw, Highlight | No, these sit on top of the page | Use Redaction Selection instead |
| Mac | File, Print, Save as PDF over a marked-up file | No, Apple says this only flattens the shape | Redact first, then export as a second step |
| iPhone or iPad | Markup: pen, highlighter, shapes, signature | No, Apple lists only drawing tools | Move the file to a Mac, or use an app built for redaction |
| iPhone or iPad | Share, Export as PDF after Markup | No, the drawing stays a separate layer | Same as above |
For a document you handle often, ONYRI Sanitize runs right in Safari or Chrome on a Mac: it reads a PDF, a Word file, or a scan, finds names, IBANs, and similar values on its own, and exports a flattened PDF with nothing left under the masks. Review the preview first. It does not read handwriting automatically, but you can mask it by hand with the “Draw an area” tool.
How do you verify a redaction on a Mac?
Before you send anything, close the file and test it the way a stranger would open it. These checks work whether you used Redaction Selection or exported flattened pages.
- Reopen the PDF, ideally in a different app than the one you used to redact it.
- Select all the text, copy it, and paste it into a plain text editor such as TextEdit. Nothing sensitive should appear.
- Search for the exact value you removed, and for a fragment of it, such as the last four digits of an account number.
- In Finder, right-click the file and choose Get Info to check its name and size; a file called lease-jane-example.pdf still gives away a name.
- In Preview, click the Info button for the file's general information, and choose Tools, Show Location Info if the page began as a photo, to see whether GPS coordinates are still attached.
- Zoom in on each redaction bar. It must be fully opaque and cover the whole value, including anything that runs into the margin.
A redaction, on a Mac or anywhere else, only reduces what a document shows. It does not by itself make the document anonymous: a job title, a date, or a place can still point to someone. When the stakes are high, ask a second person to repeat these checks before you send the file.
Frequently asked questions
Does Preview's Redaction Selection tool really remove text, or just hide it?
Per Apple's own guide, it removes the selected text “from view,” and the change becomes permanent once you close the document. Apple does not describe what happens on a scanned page, since there is no selectable text there to begin with. Test the final file with the steps above before you rely on it.
What does Markup on an iPhone or iPad actually do?
Apple's own guide lists a pen, a highlighter, shapes, text, a signature, and a loupe. Nothing on that list removes content: every tool draws on top of the page. There is no redaction feature in Markup on iPhone or iPad, so a black shape over a name is only a drawing, not a deletion.
I already sent a document with a black shape drawn over a name in Markup. What now?
Treat it as if the name was never hidden, because the file underneath may still hold it. Warn the recipient, and if the document held sensitive data, tell whoever handles data protection at your organization. Then send a properly redacted copy, made with Redaction Selection or a tool that flattens pages, and delete the earlier file if you can.
Does redacting a PDF on a Mac also remove metadata such as GPS location?
Not automatically. Redaction Selection removes only the text you select. It says nothing about the document's title, author, or a photo's location. Open the Info window in Preview, and Tools, Show Location Info for a scanned photo, to check what is still attached before you share it.
Is a redacted PDF automatically anonymous under GDPR?
Not necessarily, and the answer depends on EU law. Recital 26 of the GDPR says the rules do not apply to information that no longer relates to an identifiable person. A document with a masked name can still point to someone through a date, a role, or a place, so redaction only reduces the risk; whether the result counts as anonymous has to be judged case by case.
Sources & references
- Annotate a PDF in Preview on Mac (Redaction Selection tool)Apple Support
- Use Markup on your iPhone, iPad, or iPod touchApple Support
- View information about PDFs and images in Preview on MacApple Support
- See where a photo was taken using Preview on MacApple Support
- How to disclose information safely, version 1.2 (PDF)Information Commissioner's Office (UK)
- Regulation (EU) 2016/679 (GDPR), Recital 26EUR-Lex