Annotate PDF
Highlight important text, add sticky notes, and mark up your PDF documents.
About About the PDF Annotator Tool
About the PDF Annotator Tool
Our free online PDF annotator lets you highlight important text, underline key passages, add strikethroughs to mark content for removal, and attach sticky notes with comments. Whether you are reviewing a colleague's report, marking up a contract for revisions, studying a textbook, or providing feedback on a student's work, this tool gives you all the annotation tools you need.
The annotator provides a complete set of markup tools: choose from yellow highlighter, blue underline, red strikethrough, or add text notes with custom colors. You can navigate between pages, undo annotations you do not want, and preview your changes before downloading. All annotations are rendered directly onto the PDF pages using PDF.js and jsPDF, with all processing happening in your browser for complete privacy.
Why annotate PDFs? PDF annotations are essential for document collaboration, academic study, and professional review. Instead of printing documents and marking them up with pens and highlighters, digital annotations save paper, are searchable, can be shared instantly, and never get lost. Teachers use annotations to provide feedback on student submissions, lawyers mark up contracts for review, researchers highlight key findings in academic papers, and team members collaborate on document revisions.
How to Annotate a PDF
- Upload your PDF — Click the upload area and select the PDF document you want to annotate.
- Choose an annotation tool — Select Highlight, Underline, Strikethrough, or Note from the toolbar.
- Click to annotate — Click on the page where you want to place the annotation. For notes, enter your text.
- Download the annotated PDF — When finished, click Save to download your annotated document with all marks preserved.
Who Needs PDF Annotation
- Document review — Highlight important sections and add comments when reviewing reports, proposals, and articles.
- Academic study — Highlight key concepts, underline important definitions, and add study notes to textbook PDFs.
- Contract markup — Mark clauses for revision with strikethroughs and add comments with proposed changes.
- Collaborative editing — Share annotated PDFs with team members to communicate feedback and changes clearly.
Frequently Asked Questions
Yes. Use the color picker in the toolbar to choose any color for highlights, underlines, strikethroughs, and notes.
Annotations are rendered directly into the PDF when you download it. They become part of the PDF image, so they are permanent in the downloaded file.
Yes. Use the Undo button to remove the most recent annotation on the current page. You can undo annotations one at a time.
Absolutely. All processing happens in your browser. Your document never leaves your device and is never uploaded to any server.
Annotate PDF
Click to annotateUpload a PDF to annotate
Your file stays on your device.
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