How to annotate a PDF
- Tap "Open a PDF" or drop it onto the box. The annotation bar opens under the toolbar.
- Choose Highlight and select text, Note and click where the note goes, Pen and draw, or Text and click where the text goes. Each has its own colors.
- Made a mistake? Tap Undo, or delete any mark from the list of marks.
- Tap "Download" to save the PDF with your marks.
Good to know
The marks are standard PDF annotations: highlights, sticky notes, ink drawings and text boxes. Adobe Acrobat, Apple Preview, Chrome, Edge and phone apps show them, and can change or delete them.
They are added the way Acrobat saves comments: after the original file, which stays exactly as it was. So a digital signature on the PDF still covers what was signed.
Up to 10 marks per PDF are free. Plus and Enterprise make as many as they need.
A PDF that needs a password to open can’t take marks here. Remove the password with Unlock PDF first; Protect PDF can add it again afterwards.
Questions
Will Adobe Acrobat show my highlights and notes?
Yes. They are saved as standard PDF annotations, the same kind Acrobat makes, so Acrobat, Preview, Chrome, Edge and other PDF apps show them, and you can change or delete them there.
Can I highlight a scanned PDF?
A scan is a picture of each page, so it has no text to select. Use the pen to mark it instead.
Can I make the marks part of the page?
Yes. Download the PDF with its marks, then open it in Flatten PDF: the marks are drawn onto the page, where they can no longer be changed.
Is my PDF uploaded?
No. It is opened and marked by your browser on your device.
Page last reviewed 26 October 2026.