How to Annotate a PDF With Comments and Markup
Annotation is how you comment on a document without changing it. The mark stays a layer on top, which is exactly what you want when reviewing someone else's work.
When you review a contract, a design, or a report, you rarely want to change the text; you want to comment on it, flag a clause, ask a question, or suggest an edit. Annotation tools let you add that layer of markup on top of the PDF while leaving the original content untouched, so the author can see your feedback in context and decide what to accept.
This guide covers the annotation types and how to use them so your feedback is clear and actionable.
Match the annotation to the intent
- Highlight. Draw attention to specific text without saying anything about it; useful for marking passages to discuss.
- Comment or sticky note. Attach a written remark to a point on the page; the workhorse of document review.
- Text markup. Strikethrough to suggest deletion, underline for emphasis, and insert marks to propose additions.
- Drawing and shapes. Circle a figure, draw an arrow to a detail, or box an area, best for diagrams and layouts where words are not enough.
- Stamps. Apply a reviewed, approved, or draft stamp to signal status at a glance.
Write annotations people can act on
A highlight with no comment leaves the author guessing what you meant. Pair markup with a clear note: not just a highlight, but highlight plus this figure does not match page 3. Specific, located comments turn a review into a to-do list rather than a puzzle.
Keep each comment to one point so the author can resolve them one at a time. If you have three concerns about a paragraph, three separate comments are easier to address than one long note covering all of them.
Keep annotations separate and collaborative
Annotations live as a layer above the content, which means they can be shown, hidden, replied to, and resolved without altering the underlying document. This is the point: the author retains a clean original and a clear list of feedback. Avoid flattening annotations into the page until the review is genuinely finished, since flattening makes them permanent and un-editable.
When several people review the same file, using shared annotations rather than each marking up a separate copy prevents the nightmare of reconciling five differently annotated versions. Whoever consolidates should be able to see all comments in one place and mark each resolved.
Doing it in Atlas
The Atlas PDF studio supports highlights, comments, markup, and drawing as a layer over the document, so reviewers can give located, actionable feedback without touching the original. Because documents live alongside the projects and clients they belong to, a review happens where the work already is, and comments stay with the record rather than scattering across email. See /all-in-one.