PDF Annotator
Add your PDF file, choose any options you need, and DOC321 prepares the PDF result for you.
Annotate a PDF
Highlight passages, add text notes, and draw boxes directly on PDF pages.
Choose a PDF file to begin.
Annotate PDF pages in your browser with highlights, text notes, and boxes, then export a separate marked-up PDF.
Free PDF Annotator
Works with PDF
Get a usable PDF result
Free Online PDF Annotator: Annotate and mark up a PDF online
Annotate PDF pages in your browser with highlights, text notes, and boxes, then export a separate marked-up PDF.
Highlight important passages
Drag directly over a region of the preview to add a translucent highlight annotation-style overlay.
Add text notes and boxes
Place short text notes with a click or drag a blue box around areas that need attention.
Undo before export
All changes are queued first, so you can undo or clear them before creating the annotated PDF.
How to Use PDF Annotator
- 1Add PDF
Choose the file or content you want to work with in the hero workspace, or drag it into the upload area.
- 2Choose your options
Set only what is necessary for the result you want.
- 3Run PDF Annotator
Annotate and mark up a PDF online
- 4Use PDF
Review the result, download it, or continue into a closely related workflow.
PDF Annotator for Everyday Workflows
Purpose-built action
PDF Annotator is designed around the specific task people come to the page to finish.
Focused workflow
Everything on the page is organized around one job: annotate and mark up a PDF online.
Clear source and result
Know what goes in as PDF and what you should expect back as PDF.
Built for everyday files
Use the tool for school, office, personal, client, publishing, and administrative document tasks.
Easy to review
Check the result before you download, share, submit, print, publish, or continue into another tool.
Easy next step
Related DOC321 tools stay close by when the finished file needs another conversion, edit, or document action.
FAQs About PDF Annotator
Can I annotate a PDF online?
Yes. Open the PDF, choose a markup tool, add highlights, text notes, or boxes, then export the annotated copy.
Are these native PDF comments?
No. This version applies visible markup directly to the PDF page rather than creating separate comment objects.
Can I annotate more than one page?
Yes. Navigate between pages and keep adding markup before exporting the final PDF.
What does PDF Annotator do?
PDF Annotator is designed to annotate and mark up a PDF online. The page keeps that task, the supported PDF input, and the PDF result together in one browser workflow.
Can I use PDF Annotator online for free?
Yes. DOC321 provides PDF Annotator as a free online browser tool so you can start the supported workflow from the page without installing a separate desktop application.
Document Work Made Easier
Finished with PDF Annotator? DOC321 keeps related PDF, Word, image, spreadsheet, presentation, text, and document tools close so you can continue the workflow without starting over.
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