Annotate PDF
Mark up a PDF the way you would on paper: highlight, underline, strike through, scribble with a pen, drop sticky notes and stamp pages. Everything is flattened into the page on export, so readers do not need annotation support.
How it works
- 1
Choose a marking tool
Drag over the text area to highlight, underline or strike it, or drag freely with the pen.
- 2
Add notes and stamps
Click a page to drop a sticky note, then type its text in the side panel.
- 3
Flatten and save
Annotations become part of the page, so they display in every PDF viewer.
Your privacy is the point
This tool runs entirely in your browser using WebAssembly and Canvas. Your file is never uploaded to a server, never stored and never seen by anyone but you.
Frequently asked questions
Are these real PDF annotations?+
No — they are drawn permanently into the page content stream. That guarantees they show up in every viewer and cannot be accidentally hidden, but they are not editable annotation objects afterwards.
Can I remove a marking before exporting?+
Yes. Select it and press Delete, or use Undo. All markings are also removed if you start over.
Does highlighting keep the text readable?+
Yes. Highlights are drawn as a translucent yellow rectangle above the page, so the underlying text stays visible. Underlines and strikethroughs are thin lines.
Related tools
All toolsEverything runs locally. No uploads, no server-side copies.