Annotate PDF
Highlight text and add comments directly to your PDF documents.
How to Annotate a PDF Online
1. Select Your PDF
Click 'Choose PDF File' or drag and drop your document. Your file is loaded directly into the browser, not uploaded.
2. Select a Tool
Choose the "Highlight" tool to mark text or "Comment" to add notes. You can change your highlight color at any time.
3. Annotate & Download
Click and drag to highlight, or click to comment. When finished, click "Download PDF" to save your secure, annotated file.
Your Security is Our Priority
100% Private & Secure
Your PDF is processed entirely in your browser. No files are ever uploaded to a server, guaranteeing your data's privacy.
Instant, Browser-Based
Because there are no uploads, the tool is incredibly fast. Your annotated PDF is ready as soon as you click download.
Completely Free
Annotate unlimited PDF files for free. No watermarks (from us!), no limits, and no registration required.
Review & Collaborate with Ease
PDF annotation is crucial for academic review, business collaboration, and personal study.
Highlight Key Information
Easily mark important passages for study, review, or reference. Choose any color you want from the color picker to organize your highlights.
Add Context with Comments
Place a comment marker anywhere on the page to add questions, provide feedback, or leave reminders for yourself or your team.
Standardized Markups
Your annotations are saved in a standard format, making them visible in Adobe Acrobat, web browsers, and other PDF viewers.
Frequently Asked Questions About Annotating PDFs
Will the annotations be visible in other PDF readers?
Yes. When you click "Download PDF," our tool uses PDF-lib to embed your highlights and comments directly into the file. The final document will be a standard PDF, and your annotations will be visible in Adobe Acrobat, web browsers, and other PDF viewers.
Is it safe to edit my confidential documents here?
Yes. We built this tool with privacy as the top priority. All processing happens locally on your computer (in your browser). Your file is **never sent to our servers**, so only you can access your document.
Can I edit the text of the PDF?
This tool is for *annotating* (marking up) a PDF. It allows you to add highlights and comments on top of the existing content. It does not allow you to edit or change the original text within the PDF. For that, you would need our PDF Editor tool.