How to Black Out Part of a PDF (Free, Works on a Phone)

Published: Oct 19, 2026 | Updated: Oct 19, 2026 | About (Japanese)

Key points

Choose a PDF and drag over the parts to black out
Do the same on other pages
Create the PDF, save it and check it

Sometimes you do not want to show part of a document, such as an address, phone number or account number. With Black Out (Redact) Parts of a PDF you can hide just those parts, while keeping the PDF as a PDF.

Steps

Tap "Choose a PDF" and select one PDF.
A page is shown. Drag with your finger or mouse over the part you want to black out to draw a rectangle.

On a phone, tap "Select an area" first. While it is on, dragging does not scroll the screen.
To scroll, tap the button again.

If you make a mistake, tap "Undo last".
Move to the next page with "›" and do the same. To black out the same place on every page, tap "Apply to all pages".
Tap "Black out and create PDF", check the preview and save the PDF.

Check after saving

Open the saved PDF and try to select text over a black box. If you cannot select it, the text underneath is not there.

The original is not changed

Your original PDF stays as it is. The redacted PDF is saved separately. Keep the original file.

A black-out in a saved PDF cannot be undone.

Use "Black Out (Redact) Parts of a PDF" (free)

Tools that go well with this

Convert a PDF to Grayscale (Black & White): Turn a color PDF into grayscale or pure black and white, ready for monochrome printing, copying or fax. Choose the resolution.
Extract or Delete PDF Pages: Keep only the pages you need, or remove the pages you don't.
Compress PDF: Shrink a PDF to fit under a size you choose, for upload limits.

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