How to annotate a PDF
Add highlights, underlines, comments and drawings to any PDF — useful for review, markup and study.
Short answer: open the Annotate PDF tool or the editor and use the sidebar tools. Every annotation flattens into the page on export.
Annotation types
- Highlight — yellow or custom-colored marker, drawn as a rectangle over text. Useful for key points.
- Underline — a single line under text. Lighter than a highlight for dense documents.
- Strike-through — a horizontal line through text. Good for marking corrections or rejected clauses.
- Comment — a pinned note at any point on the page. Expands to reveal full text on hover.
- Ink — freehand drawing. Good for diagrams, arrows, check marks or signatures.
- Checkbox — a clickable checkmark. Useful for fillable forms.
- Shapes and arrows — boxes, circles, lines and arrows to point at specific content.
Review workflow
- Read the document once without annotating.
- On the second pass, highlight the paragraphs that need attention.
- Add a comment on each highlighted block explaining what needs to change.
- Use shapes and arrows for layout suggestions.
- Export and send to the author.
Style choices
Restrain your palette. Two or three colors is enough:
- Yellow — informational highlights
- Red or orange — problems or required changes
- Blue or green — confirmations, praise, or "looks good"
Will the recipient see the annotations?
Yes — because annotations are flattened into the page content on export, any PDF reader displays them. The recipient doesn't need any special software.