Editing & Signing
How to Annotate a PDF
Highlight, comment and mark up a PDF for review — and know which annotations survive when the file reaches someone else.
Annotating is how documents get reviewed: a highlight on a clause, a note asking a question, a strike-through on a paragraph that should go. The annotations sit on top of the page rather than in it, which explains most of their behaviour.
The annotation types
| Type | Use it for |
|---|---|
| Highlight | Marking text that matters without saying anything about it |
| Sticky note | A comment attached to a point on the page |
| Text box | A comment that should be visible without clicking |
| Strike-through | Marking text for deletion |
| Underline | Emphasis, where a highlight would be too loud |
| Drawing | Circling a figure, pointing at a region of a diagram |
| Stamp | APPROVED, DRAFT and similar |
Annotations are separate from the page
This is the property that surprises people. Because annotations are objects layered over the content, they can be moved, edited or deleted by anyone who opens the file — and some of them do not print by default. A reviewer's carefully placed comments can vanish from a printout entirely.
Reviewing well
- Say what you want changed, not just that something is wrong. "Unclear" is not actionable; "does this cover renewals?" is.
- Use one comment per issue, so each can be resolved independently.
- Highlight the exact text your comment refers to.
- Sign your comments if several people are reviewing the same file.
- Keep drawings for things text cannot express — a region of a plan, a direction on a diagram.
When several people review at once
Circulating one PDF to five reviewers produces five annotated files, and merging their comments is manual work. If that is your situation, either collect the reviews in sequence on one file, or move the review to a platform built for it. PDF annotation is excellent for one reviewer and awkward for many.
Before the document is published
Annotations are invisible in a casual read but present in the file. A published document still carrying internal review comments is a common and entirely avoidable disclosure. Remove annotations as part of finalising anything that leaves the organisation.
Do it now
Sign PDF
Add digital signatures to PDFs. It runs in this browser tab — your file is not uploaded anywhere.
Open Sign PDFFrequently asked questions
Will my highlights show for the recipient?+
In most readers, yes. Whether they print depends on the reader's settings — flatten if it matters.
Can annotations be edited by others?+
Yes, unless the document is flattened. They are objects on the page.
Do annotations increase file size?+
Slightly. Heavy freehand drawing adds more than text comments.
How do I remove all annotations?+
Run an optimisation pass with annotation removal, or flatten them into the page if they should stay visible.