Annotate PDF
Highlight, underline and strike through text.
Add real annotations to a PDF: highlight important passages, underline key points or strike through outdated text. Annotations are drawn over the actual text on every page.
Your files are processed locally in your browser. Nothing is uploaded to a server, ever.
Tip
Drop your file here or click to browse. Everything is processed on this device — nothing is uploaded.
Quick answers
- What does this tool do?
- Highlight, underline and strike through text. Add real annotations to a PDF: highlight important passages, underline key points or strike through outdated text. Annotations are drawn over the actual text on every page..
- Is it free?
- Yes — free and unlimited, with no account required and no watermark on the result.
- What files are supported?
- PDF files, up to 100 MB each.
- Where is my file processed?
- Entirely in your browser. Your file never leaves your device — nothing is uploaded to a server.
- What are the limitations?
- By default annotates every page; use "Pages" to limit to specific pages or ranges. The text layer is preserved, so the marks are visual annotations, not redaction.
- What happens if processing fails?
- You get a clear message explaining what went wrong and how to fix it (try another file, check the format, or start over). Your original file is never touched.
How to Annotate PDF
- Upload the PDF to annotate.
- Choose the annotation type and color.
- Leave "Pages" empty to annotate the whole document, or enter ranges like "1-3, 5".
- Click "Process" — the selected pages are annotated.
- Download the annotated document.
Frequently asked questions
Common problems and fixes
- My signature or drawing looks faint
Why: thin pen input or fast strokes produce low-contrast ink on small canvases.
Fix: draw larger than needed, use a thicker stroke, or type a signature and pick a heavier font style.
- My changes seem to have disappeared
Why: the original file was opened instead of the new download — the tool never modifies your original on disk.
Fix: look for the freshly downloaded file and use that as your new version.
- Added text does not match the document font
Why: embedded subset fonts cannot always be reproduced, so the closest standard font is offered.
Fix: pick the nearest match from the font options, or accept a slight typeface difference.
Who uses Annotate PDF?
- Anyone signing from home — contracts and forms signed on screen — files up to 100 MB, drawn, typed or uploaded as an image.
- People filling non-fillable forms — adding text on top of flat PDFs that were never designed as forms.
- Reviewers marking drafts — stamps, dates and notes before a document circulates for approval.