Annotate PDF —
highlight, comment & draw in your browser
Highlight, comment, draw, and sign PDFs — a full annotation suite that runs without uploads, without installs, and without friction.
Master Services Agreement
The annotation workspace
Every tool you need on top of your PDF — with keyboard shortcuts, layers, and collaborator comments. Zero uploads.
Pages
Master Services Agreement
Annotations · 5
Highlight · Yellow
"Acme Labs, Inc." · Page 1
Highlight · Green
Compliance clause · Page 1
Sticky note
"Check termination clause in §7"
Comment · Marta
"Redline this paragraph before signoff."
Signature · J. Chen
Signed · Page 1
Every markup you need
A complete toolkit — and every annotation is saved inside the final PDF, not as a separate file.
Highlight
Yellow, green, blue, pink — highlight text with smart line detection.
Sticky note
Pin a quick reminder or reviewer note anywhere on the page.
Comment
Threaded comments with avatars — review with your team in context.
Draw
Freehand drawing with pressure-smoothed strokes — circle, cross out, connect ideas.
Shapes
Rectangles, circles, arrows, and lines — ideal for diagrams and flowcharts.
Signature
Draw or type your signature — embeds directly into the PDF.
Three steps from open to export
No accounts, no configuration. Drop a PDF, mark it up, export — all in your browser.
Open your PDF
Drop any PDF. Contracts, research papers, meeting notes, reports. Files stay local.
Mark it up
Highlight, comment, draw, stamp, sign — every tool you need, with real-time preview.
Export the annotated PDF
Annotations embed into the final PDF — shareable with anyone, works in every reader.
One workspace — every review
From legal redlines to classroom grading — the same toolkit adapts to every document task.
Research & papers
Highlight citations, drop notes, and export marked-up PDFs for your reading list.
- Color-coded highlights
- Cross-page sticky notes
- Exported with markup
Legal review
Redline contracts, flag clauses, and leave reviewer comments for counsel.
- Section-level comments
- Shape-based redlines
- Signature for sign-off
Teaching & grading
Mark up student papers with feedback — return annotated PDFs in minutes.
- Draw corrections by hand
- Stamp grades or scores
- Export per-student PDFs
Team feedback
Threaded comments with avatars let your team review a PDF in context.
- Per-reviewer comment threads
- Annotation sidebar
- Share as annotated PDF
Exam & study prep
Highlight key points, draw diagrams, and scribble reminders on practice sets.
- Multi-color highlights
- Freehand diagrams
- Sticky reminders
Meeting notes
Annotate decks and briefs live during meetings — share annotated notes immediately.
- Fast highlight + comment
- Signature for approvals
- One-click export
Your PDF never leaves your browser
Annotation, drawing, signing, and export all happen locally. We don't have a file-storage bucket — because we never receive your file.
- ✓Rendering & markup run client-side with pdf.js
- ✓Annotations embed into the final PDF locally
- ✓No account or signup required
- ✓Works offline once the page has loaded
Annotation that respects your document
Annotating a contract or feedback round shouldn't mean uploading it to a third-party server. PDF Pro's annotation toolkit runs entirely in your browser.
| Feature | PDF Pro | Adobe Acrobat (online) | iLovePDF |
|---|---|---|---|
| Where annotations are stored | Your browser (IndexedDB) | Adobe servers | iLovePDF servers |
| Highlight, underline, strikethrough | Yes | Yes | Yes |
| Free-text annotations (rich text) | Bold, italic, color | Plain text | Plain text |
| Sticky notes & comments | Yes | Yes | Limited |
| Freehand drawing & shapes | Yes | Yes | Drawing only |
| Stamps (Approved, Draft, Confidential) | Built-in & custom | Built-in | No |
| Undo / redo with full history | Unlimited | Limited | No |
| Account required | No | Adobe ID | Optional |
| Free price tier | Unlimited | Free with Adobe ID | 1 file / hour |
Limits accurate as of early 2026. Adobe and iLovePDF are trademarks of their respective owners.
Annotating PDFs — common questions
Are my annotations saved when I close the tab?
Yes. Annotations auto-save to IndexedDB in your browser as you work, so closing and reopening the same PDF restores every highlight, comment, and stamp. To carry annotations to another device, click "Export with annotations" and the result is a flattened PDF you can share.
What annotation types are supported?
Highlight, underline, strikethrough, free text (with bold/italic/color), sticky notes, freehand drawing, lines, arrows, rectangles, circles, and stamps (built-in or custom image). Every annotation is draggable, resizable, and editable after placement.
Can I export a PDF with the annotations baked in?
Yes. Export gives you two options: "With editable annotations" (standard PDF annotation objects, editable in Adobe and any compliant viewer) or "Flattened" (annotations rendered into the page, not editable but guaranteed to look identical anywhere).
Is there an Undo and how far back does it go?
Ctrl+Z (Cmd+Z on Mac) undoes any annotation action — placement, drag, edit, delete. The history goes back to when you opened the PDF in the current session, with no fixed step limit.
Can I collaborate with someone else on the same PDF?
Not in real-time — annotations are stored locally for privacy. The standard workflow is: annotate → export with annotations → share via Secure Transfer (encrypted in your browser before upload). The recipient sees your annotations in their own viewer.
Do annotations work on scanned (image-only) PDFs?
Yes. You can highlight regions, draw, comment, and stamp scanned pages just like searchable PDFs. To highlight specific text on a scan, run OCR first (Convert tool with OCR enabled) — that produces a searchable PDF you can highlight word-by-word.
Can I make custom stamps (e.g. with my logo)?
Yes. Open the Stamp tool, choose "Custom", and drop in a PNG or SVG. The image becomes a reusable stamp you can place at any size on any page. Custom stamps are stored locally in your browser, not on our servers.
Open a document. Start marking up.
No signup. No upload. No install. Full annotation toolkit — right in your browser.