How to redact a PDF on Android
On Android, drawing on a PDF does not redact it. See what Drive, Files and Acrobat Reader do to the text, and how to test your file before you send it.
As of October 2026, Google's help pages for Drive and Files by Google describe no way to redact a PDF on Android. Both apps only draw on top of the page, so the words stay in the file and anyone can search, select or copy them. To redact on a phone, use a tool that deletes the text or turns each page into a picture, then test the file.
Why does a pen stroke or black highlight not redact a PDF?
A PDF stores the words on a page as real text. When you draw over them with a finger, the app adds a mark on top and leaves the text alone. Google's Drive help page lists a pen, a highlighter and an eraser, plus a switch to show or hide all annotations.
The UK Information Commissioner's Office (ICO) makes the same point in its guidance of 31 July 2025. The information “remains in the electronic file if it is only covered by a shape”, such as a black rectangle. So if Jane Example covers her IBAN with finger-drawn bars in the Drive app, her landlord may still be able to copy it.
Here is a one-minute test for any file:
- Touch and hold a word under a bar. If the viewer selects it, the text is still there.
- Search for a masked word. If the viewer finds it, the word is still in the file.
- Copy a block around the bar and paste it into a notes app. Nothing sensitive should appear.
What do Google Drive and Files by Google do with a PDF?
Google's help page on annotating PDFs in Drive says the feature needs Android 6.0 or later. The toolbar has a pen, a highlighter, an eraser, undo and redo, and a switch to show or hide annotations. The page never mentions redaction.
Files by Google has the same pen, highlighter and eraser. Its help page adds two details. The More menu has “Find in file”, which searches the text of the PDF. And “Save copy” uploads the annotated copy to your Google Drive, while the original stays unmarked on your device.
Does Adobe Acrobat Reader for Android redact a PDF?
No Adobe page we read says the Android app has a “Redact” tool. Adobe's Google Play listing, updated on 29 September 2026, never uses the word redact. It names comments, sticky notes, highlighting and Fill & Sign among the features that need no subscription. Editing text and images is paid.
Adobe's redaction guide names Acrobat Pro and says redacted information is permanently deleted once you click OK. It never mentions Android. If you find a redaction tool in the app, use it on a copy and run the checks below.
Which Android methods leave the text in the file?
| Method on Android | What happens to the text | Safe to share? |
|---|---|---|
| Pen, highlighter or comments in Drive, Files or Acrobat Reader | It stays in the file. They are marks on top of the page. | No |
| A Redact tool, if your app has one | It should delete the text. Verify it. | Yes, after the checks |
| Screenshot with a solid bar, saved as a new image | There is no text layer, and the bar replaces the pixels. | Yes, if the bar is fully opaque and you send only the new image |
| Web tool that uploads the file | It depends on the tool. Your file is copied to its servers. | Only if you accept that copy |
| Browser tool that rebuilds pages as images | The text is gone. Each page is a picture with the masks painted in. | Yes, after the checks |
Can you redact a PDF in an Android browser?
Yes, but two kinds of web tools look alike. An upload tool sends your PDF to a server, works on it there and sends the result back. A browser tool works on your phone, and the file stays there. The security page of iLovePDF, for one, says processed files are “automatically and permanently deleted within two hours of being processed”. So the file does leave your phone.
Lower Saxony's data protection authority (Germany, July 2025) lists online tools that need the original file in the cloud among unsuitable methods. To tell the two kinds apart, read the tool's privacy page for words like upload, our servers and deleted after. A promise that nothing leaves your device is only the vendor's word.
ONYRI Sanitize is a web app, so it runs in the browser of an Android phone. Its rule-based detectors, manual tools and flattened export run on the device, so the file is not uploaded. For the manual tools, choose “Text” and tap a word, or choose “Area” and drag a rectangle with your finger. One limit: the name-recognition model does not run on phones. Check every name yourself and add missed ones with “Also mask”.
What should you check on your phone before you send the file?
Run these checks on the file you will send, not on the one you worked on.
- Open the new file in a different PDF viewer.
- Search for each masked word and for a fragment, such as the last four digits of a number. Files by Google has “Find in file”.
- Touch and hold words under a bar, then copy a block into a notes app. Nothing sensitive should appear.
- Zoom in on every bar on every page. Each must be opaque and cover the whole value, headers and footers included.
- Read the file name. A name like lease-jane-example.pdf gives the person away, so rename the copy.
- Check which file the share sheet will send. Files by Google says the original stays unmarked on your device, so it still shows everything. Pick the redacted copy.
- For high stakes, ask a second person to repeat steps 2 to 4.
A clean result is a good sign that the text is gone. It does not mean the person is anonymous, because a date, a job title or a place can still point to someone. Recital 26 of the GDPR (EU) says to weigh all means reasonably likely to be used to identify a person. For a legal disclosure, ask your data protection officer or a lawyer.
Frequently asked questions
Does Android have a built-in way to redact a PDF?
As of October 2026, the help pages for Google Drive and Files by Google describe a pen, a highlighter and an eraser. Neither mentions redaction. Treat them as drawing, not deletion. For other apps, run the one-minute test.
Is a screenshot of the page a safe copy?
It can be. A screenshot is a picture, so it has no hidden text. The ICO advises a solid colour block, then exporting to a format without layers or edit history, such as PNG or JPEG. Lower Saxony's authority recommends 100 % opacity and warns that blur can sometimes be reconstructed.
Does the test work on a scanned PDF?
Not on its own. A scan is a picture, so selecting and searching may find nothing. That does not make it safe. If your black mark is an annotation, it can be hidden, and the page underneath is untouched. Only a copy with the mark painted into the pixels is safe.
Can I print the page, black it out and scan it?
Yes, as a fallback. Lower Saxony's authority warns that a black pen often leaves text readable, for example against a lamp or after a scan with digital filters. It advises sticking something over the passages or cutting them out, then sending only the copy or the scan.
Sources & references
- Annotate PDFs with a stylus or freehand on AndroidGoogle Drive Help
- Open, manage & edit PDFs in Files by GoogleFiles by Google Help
- Adobe Acrobat Reader: Edit PDF (store listing, updated 29 September 2026)Google Play, Adobe
- How to redact a PDFAdobe
- How do we avoid an accidental breach when redacting information? (31 July 2025)Information Commissioner's Office (UK)
- Security and data protection (section: Data Retention and Removal)iLovePDF
- Hinweise zum Schwärzen von Dokumenten (July 2025, in German)Der Landesbeauftragte für den Datenschutz Niedersachsen (Germany)
- General Data Protection Regulation, Recital 26gdpr-info.eu