Annotate PDF – Free Online PDF Annotator
Mark up PDFs right in your browser.
Highlight passages, draw freehand, drop sticky notes, add shapes and arrows, place typed comments — then save one clean annotated PDF. Free, private, nothing uploaded.
Drop your PDF here
or choose a file from your device
Annotation happens in this tabOpen your PDF
Drop the file in, or try the sample contract with two pages.
Pick a tool & mark it up
Highlight, draw, drop sticky notes, add shapes, arrows and typed text — choose colors and widths as you go.
Save one PDF
All your marks are baked in and a notes summary page is appended. Download and share it anywhere.
Related Tools You Might Need
How to Annotate a PDF Online Free: The Honest Way
Picture this: your client sends the contract back as a PDF and asks you to "mark the bits you disagree with." Or your professor returns your thesis draft and you want to scribble thoughts right on the pages. Or a friend shares a floor plan and you need to point at the wall that has to go. Printing, scribbling with a pen, and scanning it back is the 2009 way. This is the faster way.
This tool lets you highlight passages, draw freehand circles and arrows, drop numbered sticky notes, and place typed comments directly on your PDF — then saves one clean PDF with everything baked in. No account, no watermark, and your document never leaves your browser. Here is how it works.
- Open your PDF. Drag the file onto the drop zone, or click "Try a sample PDF" to play with a two-page sample contract first.
- Pick a tool and mark up. Highlight key lines by dragging over them, freehand-draw circles around figures, click to drop numbered sticky notes (write the note text in the side panel first), draw rectangles, lines and arrows, or click anywhere to place typed text. Colors and line widths are yours to choose.
- Save the annotated PDF. One click bakes every mark into the file. If you used sticky notes, a neat "Annotation Notes" summary page is appended at the end listing each note with its page number.
Real Situations Where This Saves You
Reviewing contracts and quotes. Highlight the clauses you want changed, drop a numbered note on each one, and send back a single PDF that says exactly what you mean — no long email chain needed.
Studying and exam prep. Highlight definitions in your textbook PDF, circle the tricky formulas, add margin notes in your own words. Everything stays in one file you can reopen anywhere.
Teacher feedback on assignments. Circle the weak paragraph, draw an arrow to the margin, drop a note explaining what is missing. Students see feedback in context, not in a separate document.
Design and plan reviews. Floor plans, wireframes, mockups: mark what moves, what stays, what needs a second look — with shapes and arrows that land exactly where you put them.
Good to Know
Annotations are baked in (flattened). When you save, your highlights, drawings and notes become a permanent part of the PDF pages — they look identical in every reader, on every device. The trade-off: they are not "live" comments you can edit or delete later in Adobe Reader. If you need to change something, come back here and redo that mark.
Sticky notes get a summary page. Each note appears as a numbered yellow square on the page, and the tool appends an "Annotation Notes" page at the end of the PDF listing every note with its page number. Perfect for review meetings.
Your PDF never leaves this tab. Rendering, drawing and saving all happen on your own device. Password-protected PDFs are refused upfront — the tool will simply tell you it cannot open them, rather than failing halfway.
Scanned PDFs work too. A scan is just a picture of a page, and you can highlight and draw over pictures as happily as over real text. (If you need the text itself to be selectable and searchable, run the file through the JPG to Word OCR tool first.)
Undo is your friend. Every mark can be undone one step at a time, or wiped per page or for the whole document, before you save.
Common Questions
Is annotating PDFs really free?
Yes. No account, no watermark, no limits on how many PDFs you mark up or how many annotations you add (up to a generous 2,000 per file).
Does my PDF get uploaded to a server?
No. The entire process — rendering, drawing, baking and saving — runs inside your browser. Your document never travels anywhere.
Can I edit my annotations later in Adobe Reader?
Not as live comments, no. They are flattened into the page, which is exactly what makes them look identical everywhere. To change a mark, reopen the file here and annotate again.
What if I make a mistake while drawing?
Hit "Undo last" to step back one mark at a time, or clear a whole page and start it fresh. Nothing is permanent until you press "Save annotated PDF."
Do the sticky notes show up on the page itself?
Yes — as small numbered squares exactly where you clicked. The full text of every note is also collected on the appended "Annotation Notes" summary page with page numbers.