How to black out text in a PDF on iPhone so it cannot be copied

The short answer

In most markup and annotation tools, the black rectangle you draw is stored as a separate object on top of the page. The original characters stay in the file underneath, so the covered words can still be selected, copied, or found with a search — and the box itself can often be dragged away or deleted. To remove the text rather than cover it, you need a tool that builds a new exported copy in which the covered content no longer exists.

Check any PDF in about fifteen seconds

Before you forward a file you covered up, open the copy you are about to send and run these three checks. They take longer to read than to do.

1. Try to select it. Drag across the blacked-out area. If a selection highlight appears, there is still text there.
2. Try to search it. Search the document for a word or number you meant to remove. If it is found, it is still in the file.
3. Try to move the box. Tap and drag the black shape. If it moves or can be deleted, whoever receives the file can move it too.

Any one of these means the document is covered, not redacted. Do not send it.

The situations where this matters most

• Forwarding a bank or card statement with a balance or account number on it.
• Sending a form that carries a Social Security or tax identification number.
• Sharing a contract or letter that names a person who should not be named.
• Attaching a screenshot or scan that shows an address, a phone number, or a signature.

In each case the person receiving the file only has to select and copy to recover what you thought you had removed.

A redaction workflow that holds up

1. Keep the original. Redact into a new file; never overwrite your only copy.
2. Mark everything that must disappear. Select the text where the PDF has a text layer, and draw over anything selection cannot reach — logos, handwriting, scanned regions.
3. Export a rebuilt copy. The export should produce a new file, not a saved annotation layer.
4. Re-run the three checks above on the exported copy.
5. Read the visible pages one more time. Redaction removes what you marked. It cannot know what you missed.

Redact PDF: Hide the Sensitive, for iPhone and iPad

Redact PDF is a one-time $8.99 App Store purchase for iPhone and iPad running iOS 17 or later. There is no subscription, no in-app purchase gate, and no account.

You open a PDF from Files, select text to redact where the document has a text layer, draw boxes or straight bars over anything selection cannot catch, and preview the generated copy before you share it. The app renders each page as an image, burns the black bars into that image, and rebuilds a new image-only PDF. Your original file is never changed.

After exporting, the app re-opens the generated PDF on your device and checks it for selectable text, redacted text strings, remaining annotations, and document metadata — and warns you not to share the file if that check fails. Redaction happens locally on your device; documents are not uploaded, and there is no account, no analytics, and no ads.

You can also read the Redact PDF product details before opening the store.

Know the trade-offs and the limits

• The exported copy is image-only. It does not preserve the original text layer, annotations, links, form fields, attachments, or PDF object structure — so the redacted file is not searchable or fillable. Keep your original for anything that needs those.
• Redaction removes visible content you mark. It is a different job from cleaning hidden document information such as author names, comments, or tracked changes.
• Redact PDF is a practical privacy tool. It is not legal advice, compliance software, or a forensic guarantee, and it does not certify a document for any filing or regulatory standard.
• Always review the exported PDF yourself before you send it.

If your concern is the hidden information inside a document rather than the words on the page, see how to remove metadata from Word and PDF files before sharing.