Annotate PDF Online Free
Annotate PDFs free — highlight, underline, draw, add sticky notes, comments, signatures and shapes for study and review. In-browser.
Drop your PDF here
or press Ctrl+V to paste
or
🔒 Secure — processed locally in your browser, never stored or reused.
Ready to annotate
Select a PDF to begin
0 files
0 pages
—
document.pdf
100% Private
Zero server uploads. Your data stays on your device.
Rich Annotations
Highlight, underline, draw, sign, comment, stamp and redact.
Undo & Edit Anytime
Review, edit or remove any annotation before exporting.
Free & Unlimited
No sign-ups, no watermarks, no usage limits.
AFFLIGO Annotate vs Kami & Xodo
AFFLIGO
- ✓Highlight + strikeout + redaction tools
- ✓Pen, stamps, sticky notes & e-sign pad
- ✓Flattened export, identical everywhere
- ✓In-browser, no signup, no caps
Kami
- ✗Full markup set needs paid plan
- ✗Full toolkit in classroom plans
- ✗Export with free-plan limits
- ✗Free caps per-file tools
Xodo
- ✓Highlight + sign free
- ✗Power tools need Pro
- ✗Standard export, sync needs account
- ✗History behind login
How to Annotate a PDF
Step 1
Upload PDF
Drag & drop or click to select your PDF file — sizing adapts to your device.
Step 2
Annotate
Highlight text with the highlighter, draw on pages with the pen, mark up with shapes, add sticky notes, sign, or redact.
Step 3
Export
Export your annotated PDF with all highlights, notes, and signs preserved.
When to Use This Tool
Document Review
Add comments, highlights, and notes when reviewing contracts or proposals.
Feedback & Editing
Mark up drafts with correction marks, suggestions, and revision notes.
Study Notes
Students and teachers highlight textbooks, mark assignments, and share feedback on papers.
Signature Fields
Draw signatures, add text fields, and mark signature areas on forms.
Tested by the builder: I marked up a 10-page contract — highlights, strikethroughs, text notes, a drawn signature, and one redaction all survived export into a single _annotated.pdf, and Ctrl+Z cleanly undid a misplaced shape before saving. One PDF is edited at a time; use Replace to switch files. Printing is intentionally disabled inside the editor — export first, then print the downloaded file. No Adobe Acrobat or signup needed. To change existing text instead of marking it up, use the PDF editor.
Frequently Asked Questions
Yes. The browser editor runs on Mac, Windows, Linux, and Chromebooks with mouse or trackpad — plus touch and stylus on iPhone, Android, and iPad, where Apple Pencil works for freehand. Highlight, draw, place text or signatures, then export the finished PDF. No app install needed on any device.
Highlight, underline, strikethrough, freehand drawing, text boxes, shapes (rectangles, circles, arrows), signature pad, stamps, sticky notes & comments, and redaction. All with custom colors and opacity — a complete free PDF annotator.
Yes. Each tool supports custom colors, opacity, and line thickness to match your annotation style.
Yes. Click any annotation and press Delete. Undo (Ctrl+Z) also works for any action before exporting.
Yes. Draw, type, or upload your signature with the built-in signature pad, then place it anywhere on the page. The signature is embedded into the PDF you download.
Click Export after annotating — the file saves to your device with all markups flattened into the pages. Print the downloaded file from any PDF reader afterwards.
Select the highlighter from the toolbar, pick a color and opacity, then click and drag over the text. Highlights flatten into the page on export, so they look identical in any reader.
Yes. Pick the pen (freehand) tool, set color and thickness, and draw directly on the page — signatures, sketches, and handwritten notes all work. Touch and stylus input draw the same as a mouse.