Use ThePDFBuddy to annotate PDF files online with simple tools for text, notes, highlights, drawings, shapes, comments, and signature-style images. It is useful for reviewing documents, studying, proofreading, signing workflows, and giving feedback without installing heavy PDF annotation software.
or click to browse (Max 50MB)
This annotation tool processes your PDF in the browser. Other tools may work differently depending on the conversion.
PDF annotation means adding comments, notes, highlights, drawings, shapes, or markup on top of a PDF without rewriting the original document content. It is useful for document review, study notes, proofreading, contract feedback, form correction, research paper markup, and team collaboration.
Add highlights, text, note boxes, freehand drawings, rectangles, circles, lines, arrows, and images to your PDF documents.
Choose from any color and adjust line thickness for your annotations. Make your markup stand out with custom styling.
Made a mistake? Undo your last action or redo it. Full history support while annotating gives you complete control.
Where supported, the annotation workflow runs in your browser so you can review and mark up documents quickly.
All annotations are embedded directly into the PDF file. They become part of the document permanently, just like native PDF markup.
Our tool is fully responsive and works perfectly on desktop, tablet, and mobile. Annotate anywhere, anytime.
Add notes, arrows, and comments to proposals, reports, contracts, and forms before sharing feedback with a team or client.
Highlight PDF notes, mark research papers, add study comments, and circle important ideas while reading course material.
Use text boxes, notes, highlights, and shapes to call out clauses, corrections, approvals, and follow-up questions.
Draw on PDF pages, point to mistakes, add correction notes, and mark personal PDF reminders before final export.
Where supported, ThePDFBuddy processes PDF files directly in your browser, helping you work with documents privately and quickly. For best privacy, avoid uploading sensitive documents to any online tool unless you are comfortable with the processing method.
50MB per file
PDF 1.3 through PDF 2.0, PDF/A
Highlight, Text, Note, Freehand Drawing, Rectangle, Circle, Line, Arrow, Images
This annotation tool processes your PDF in the browser
Chrome, Firefox, Safari, Edge, and all modern browsers
Close or refresh the tab to clear the active browser session
Use this PDF editor to annotate source files before or after AI-assisted review. Helpful next reads include How AI Is Changing PDF Editing and Document Management, PDF AI vs Traditional PDF Tools, and AI PDF Filler.
