Skip to main content

ANNOTATE PDF

Annotate PDF

Add highlights, comments, drawings, shapes, stamps and signatures to PDFs

Loading PDF Annotator…

Preparing tools — PDF rendering starts after you upload a file.

  • 100% Secure

    Files are processed privately and deleted automatically after retention.

  • Real PDF Annotations

    Annotate the actual PDF and export without fake sample previews.

  • Keep Text Searchable

    We avoid full-page rasterization so original text stays selectable when possible.

  • No Install Required

    Annotate PDFs in your browser on desktop, tablet, or mobile.

How to Annotate a PDF?

  1. 1

    Upload

    Drag & drop or choose a PDF file to open in the annotator.

  2. 2

    Add Annotations

    Highlight text, add comments, draw, stamp, and sign on real pages.

  3. 3

    Review & Edit

    Use undo/redo, page thumbnails, and the comments panel to refine.

  4. 4

    Download

    Export a new annotated PDF. The original file is never overwritten.

A practical online PDF annotator

OneFileKit Annotate PDF renders your uploaded PDF with PDF.js and lets you place highlights, underlines, strikethroughs, text, sticky notes, freehand drawings, shapes, arrows, stamps, and signatures on top of real pages.

Annotations are stored separately from the PDF rendering layer and exported with vector/PDF-level operations where possible. We do not claim every annotation is a native PDF annotation when it is flattened visually for compatibility.

Comments appear in the side panel with author and timestamp, and can be edited or deleted before export.

Security & privacy

  • Uploads are validated by extension, MIME type, and PDF structure.
  • Password-protected PDFs require unlock for the current job only.
  • Comment and annotation text is treated as untrusted input and escaped on export.
  • Downloads require a secret token bound to your job.
  • Temporary files and drafts expire after a configurable retention period.

Related PDF Tools