Annotate PDF online

Highlight passages, scribble in the margin, circle what matters and pin comments for someone else to read. A PDF annotator that works on scans too.

Runs in your browser. Your PDF is never uploaded. No sign-up, no watermark.

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The annotation tools

Highlight
Drag a box over a line. Uses a see-through yellow-green with a multiply blend, like a real highlighter, so text stays legible in print.
Draw
Freehand ink in four widths and five colours: underline, circle, arrow, margin notes.
Comment
A sticky note pinned to a spot. Saved as a real PDF comment with your text, visible in the comment list of Acrobat, Preview and browser viewers.
Shapes & arrows
Arrows, straight lines, boxes and ellipses to point at, frame or underline anything.
Check, Cross, Dot
Quick marks for marking up a checklist or grading a worksheet.
Text
Typed notes directly on the page, when handwriting would be hard to read.

How to annotate a PDF for review

  1. Open the PDF above; Highlight is ready.
  2. Highlight the passages that need attention.
  3. Pin a comment beside each one saying what should change. The Comments panel lists them by page.
  4. Download and send it back. The recipient sees your marks and can reply to the comments in their own reader.

Highlight colours that survive printing

Bright yellow-green is used because it has the highest lightness of any highlighter colour, which keeps black text above it readable both on screen and on a black-and-white laser printer, where it prints as a very light grey. Darker marks (blue, red) are better done with the Draw tool as underlines, so they don't bury the words.

For reading notes that don't belong on the page at all, open the Notes panel: it keeps a notepad per page in your browser.

Questions people ask

Will my highlights and comments show in other PDF readers?

Highlights and drawings are written into the page, so they look the same everywhere. Sticky comments are saved as standard PDF text annotations, which Adobe Acrobat, macOS Preview, Chrome, Edge and Firefox all list and open.

Can I highlight text on a scanned PDF?

Yes. The Highlight tool draws a box, so it works on scans and images of text as well as on real text. Because it uses a multiply blend, the words underneath stay readable.

How do I draw a straight line, arrow or circle on a PDF?

Choose Shapes, then Arrow, Line, Box or Ellipse, and drag on the page. For freehand marks use Draw. Anything you add can be moved with Select or removed with Undo.

Can I annotate on an iPad with a stylus?

Yes. Apple Pencil and other styluses work with the Draw tool, and the page does not scroll while you draw.

Other things you can do here