All articles
How-To4 min read

How to Annotate a PDF Online

Annotating a PDF — adding notes, highlights, and drawings — doesn't require Acrobat. You can do it entirely in your browser for free, with no uploads.

Published April 12, 2025

What Types of Annotations Can You Add?

PDF annotations fall into a few categories: text notes (typed comments placed anywhere on the page), freehand drawings (pen strokes in any colour), and highlights (semi-transparent coloured rectangles over text). Our browser-based Annotate tool supports all three without installing any software.

Adding Text Annotations

Text annotations are the most versatile type — you can place a typed comment anywhere on a page. They're ideal for marking up contracts, review drafts, study materials, or anything where you want to leave a specific note attached to a location on the page.

  • Open the Annotate tool and load your PDF
  • Select the Text tool from the toolbar
  • Click anywhere on the page to place a text box
  • Type your annotation — adjust font size and colour as needed
  • Click Save to download the PDF with all annotations embedded

Highlighting a PDF

Highlights are coloured transparent rectangles drawn over text. Use them to mark important passages, indicate sections to review, or colour-code different topics. Different colours work well for different categories — for example, yellow for key facts, green for action items, red for issues.

Freehand Drawing

The draw tool lets you sketch freely on any page — useful for circling items, drawing arrows to point to something, or adding hand-drawn diagrams. On touch screens and tablets it works especially well with a stylus. Adjust the stroke width and colour before drawing.

Are Annotations Permanent?

Annotations added with our tool are baked into the PDF when you download it — they become permanent page content. This is ideal for sharing: the recipient sees the annotations in any PDF viewer with no special software. If you want reversible annotations, work on a copy and keep the original clean.

Annotating vs. Commenting (Sticky Notes)

Traditional 'sticky note' comments in Acrobat are separate metadata objects — recipients can delete them or hide them. Embedded annotations (text, drawings) are content — they can't be hidden without editing the PDF. For collaborative review workflows, sticky notes are better. For sharing a marked-up final document, embedded annotations are more reliable.

Try it yourself — free & private

No sign-up, no upload. Everything runs in your browser.

Annotate PDF

Frequently Asked Questions

Can I annotate a scanned PDF?+

Yes. Annotations are drawn on top of the page image regardless of whether the PDF is a text document or a scanned image. For scanned PDFs you can't select the underlying text, but you can still draw, highlight areas, and add typed notes.

Can I move an annotation after placing it?+

Text and signature annotations can be repositioned by clicking and dragging. Use Ctrl+Z to undo any annotation.

Can multiple people annotate the same PDF?+

You can annotate a PDF, download it, and pass it to the next person to add their annotations using the same tool. Annotations from all reviewers will be combined in the final file.

Will annotations be visible in Adobe Reader?+

Yes. Because annotations are embedded as page content (not as separate Acrobat comment objects), they appear identically in every PDF viewer — Adobe Reader, browser viewers, Preview on Mac, and anywhere else.

annotatehighlightnotesdrawcomments

Related Articles