How to Annotate PDFs Online Free

When PDF annotation is useful

Marking up documents for review, adding feedback, highlighting important sections, adding sticky notes, and collaborating on documents with others.

Step-by-step guide

1. Open the Annotate PDF tool 2. Upload your PDF 3. Select annotation tool: highlight, underline, strikethrough, comment, or shape 4. Click and drag over text to apply highlighting 5. Click anywhere to add sticky note comments 6. Download the annotated PDF

Annotation types

Highlight: Mark important text in yellow or custom colours Underline: Draw attention to specific lines Strikethrough: Indicate text that should be removed Comment: Add floating notes that appear when clicked Shapes: Draw boxes, circles, and arrows

Best practices

Use different colours for different reviewers — each person uses a unique highlight colour Keep annotations professional — avoid personal comments in formal documents Flatten annotations before sharing — makes markup permanent and uneditable

FAQ

Can others see my annotations? Yes. Annotations are saved as part of the PDF file and will be visible to anyone who opens it.

Can I remove annotations later? Yes, if you have the original unflattened file.

Will annotations work in all PDF viewers? Standard annotations work in Adobe Reader, Chrome, Firefox, and all modern PDF software.