katlab tools/annotate

Annotate · PDF

Draw, highlight, add text, shapes and signatures — and permanently redact — right in your browser. Nothing is uploaded.

Files are processed locally. Nothing is uploaded to a server.
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A free, private PDF annotator

Mark up any PDF without uploading it. Draw freehand, highlight, add text and shapes, drop in a signature, and redact sensitive content — every action runs inside your browser tab, so the document never touches a server.

How to annotate a PDF

  1. Drop a .pdf onto the box above.
  2. Pick a tool — pen, highlighter, text, shapes, whiteout, redact or signature — set the color, size and opacity, then draw on the page.
  3. Move between pages in the sidebar, undo anything you don't like, then click Download annotated PDF. Nothing is uploaded at any point.

True redaction, not a black box

Most "redaction" tools simply draw a black rectangle over the text — the words are still in the file and can be selected, copied or extracted. This tool does it properly: any page you redact is re-rendered to a high-resolution image with the covered area painted out, so the original text is permanently gone. Pages you don't redact keep their selectable text, and document metadata is cleared on export.

Sign a PDF three ways

Draw your signature with a mouse, finger or stylus; type your name in a handwriting font; or upload a photo of your signature and have the background removed automatically. Then drag it to size and place it anywhere on the page.

Are password-protected PDFs supported?

Encrypted PDFs can't be opened directly — remove the password in your PDF reader first, then annotate here.