Annotate PDF Online for Free
Highlight, comment, and mark up any PDF without leaving your browser.
Drag files here or click the button
Maximum file size: 100 MB
No account, no watermark. Your files are not stored on our servers after processing.
Reviewing a document usually means more than reading it - you need to flag a paragraph for a colleague, leave a comment explaining why a clause needs revision, or circle a figure in a report that doesn't add up. PDF Guru's annotation tool lets you highlight text, draw shapes, add sticky notes, underline key passages, and drop free-text comments straight onto the page, all without converting the file or installing a separate PDF reader with paid markup features.
This works well for anything passed back and forth for feedback: student papers being graded, legal drafts under review, or design proofs waiting on client sign-off. Because the tool runs in your browser, there's no upload delay and no file sitting on a remote server afterward. It handles documents up to 100 MB, so long reports and multi-page proposals work just as smoothly as a single-page memo, and no account is needed to get your marked-up file back.
How to use Annotate PDF online
- 1
Open your PDF in the tool
Upload the file from your device; it renders immediately in the browser so you can start marking it up right away.
- 2
Choose an annotation tool
Pick highlight, underline, strikethrough, freehand drawing, shapes, or sticky notes from the toolbar depending on what you need to flag.
- 3
Mark up the pages
Click or drag over the relevant text or area, then type any comment text into notes so reviewers understand your reasoning.
- 4
Save your annotated PDF
Export the file once all pages are reviewed. The annotations are embedded in the PDF so anyone can view them later.
When people use this tool
Reviewing contracts before signing
Highlight clauses that need renegotiation and leave comments explaining specific concerns for a colleague or client to address.
Grading student assignments
Underline errors, add margin comments, and circle sections that need revision without printing a single page.
Marking up design proofs
Draw arrows and boxes around layout issues in a PDF proof so the design team knows exactly what to fix.
Collaborative document review
Multiple reviewers can annotate copies of the same PDF, and each set of comments stays visible when the file is opened later.
What you get
Full highlighting toolkit
Highlight, underline, and strikethrough text in different colors to distinguish between types of feedback at a glance.
Sticky notes and comments
Attach free-text notes to specific spots on a page for detailed explanations that wouldn't fit as a simple highlight.
Freehand drawing and shapes
Circle, box, or draw arrows directly onto diagrams, images, or tables to point out exactly what needs attention.
Browser-based, no plugins
Everything happens in the tab you're already using - no PDF reader plugin or desktop software install required.