Annotate PDF

About PDF Annotation Tool

This free online PDF annotation tool lets you add various markups to your PDF documents. You can add text notes, highlight important sections, underline or strikethrough text, draw shapes like rectangles and circles, add arrows to point to specific areas, and even draw freehand. All processing happens in your browser - your files are never uploaded to any server.

What annotation tools are available?

You can use: Text (add text anywhere), Highlight (yellow highlighter), Underline, Strikethrough, Freehand Pen (draw freely), Rectangle, Circle/Ellipse, Arrow, and Line. Each tool supports custom colors, sizes, and opacity levels.

How do I add text to a PDF?

Select the Text tool from the toolbar, click anywhere on the PDF page where you want to add text, type your text in the input box that appears, then click Add to confirm. You can change the font size and color before adding.

Can I highlight text in the PDF?

Yes! Select the Highlight tool, then click and drag over the area you want to highlight. The highlight uses a semi-transparent yellow color by default, but you can change the color and opacity.

How do I draw shapes?

Select Rectangle, Circle, Line, or Arrow from the toolbar. Click and drag on the PDF to draw the shape. You can customize the color, line thickness, and opacity.

Can I undo annotations?

Yes! Click the Undo button to remove the last annotation on the current page. You can also click Clear Page to remove all annotations from the current page, or Clear All to remove all annotations from the entire document.

What is the maximum file size?

The maximum file size is 50MB. For larger files, consider compressing the PDF first.

Is my PDF file secure?

Absolutely! All annotation processing happens locally in your browser. Your PDF file is never uploaded to any server, ensuring complete privacy and security.

Does it work on scanned or rotated PDFs?

Yes. The tool reads each page's rotation flag, so annotations and stamps land in the correct place on pages rotated 90, 180, or 270 degrees - common in scanned, legal, and CAD documents. Note that markup on a scanned image is drawn on top of the image; the underlying scan stays as-is.

Are annotations flattened into the PDF or kept as an editable layer?

Annotations are flattened (burned) directly into the page content using pdf-lib. They become part of the document and cannot be moved or deleted by a later PDF reader, which is what reviewers and document-control teams usually want. Existing content, form fields, and pages you do not touch are preserved.

Can I add Bates numbers or 'Page X of Y' across the whole document?

Yes. Enable Page Stamping, pick Bates (prefix + zero-padded number), 'Page X of Y', or number only, choose a corner and start number, then apply. The stamp loops over every page at export with a consistent sequential identifier - ideal for legal discovery and engineering submittals.

Is text searchable after export, and are existing fields kept?

Text you add and Bates stamps are real PDF text, so they stay selectable and searchable. The tool only adds your markup on top of the original - it does not rasterize or strip the existing page content or form fields.

Can I preview before downloading?

Yes! After applying annotations, you can preview the annotated PDF directly in the browser before downloading. Use the fullscreen button for a larger view.