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Comment PDF
Add comments and annotations to your PDF documents. Click on the PDF to add sticky notes and comments. Your files are processed in your browser - nothing is uploaded to any server.
How PDF annotation works in this tool
When you click a location on a PDF page, the tool records the position as a coordinate relative to the rendered canvas. On download, those coordinates are converted to PDF page space and written as standard PDF Text annotation objects, the same annotation type used by Adobe Acrobat and other PDF editors. Each comment has a linked Popup annotation that stores the text content. The result is a PDF with native annotations that open as sticky notes in any standard PDF viewer.
No file is uploaded. The PDF is loaded, annotated, and downloaded entirely in the browser.
Comment PDF online - add sticky notes to any PDF
Open a PDF, click any location on the page to place a comment marker, type your note, and download the annotated file. Comments are embedded as native PDF Text annotations compatible with Adobe Acrobat, Preview, Foxit, and other standard viewers.
Features
- Click anywhere on the page to place a comment at that exact position
- Comments are standard PDF Text annotations, readable by any PDF viewer
- Existing annotations in the original PDF are preserved and displayed
- Navigate multi-page documents and add comments to any page
- Edit or delete individual comments before downloading
- All processing happens in the browser, the file is never uploaded
When to use this tool
Use it to mark up a draft, leave review feedback on specific sections, or annotate a document before sharing it. Because the output uses standard PDF annotation format, recipients can read comments in any PDF viewer without special software.
If you need to prepare the document first, you can merge multiple PDFs into one or reduce the file size before annotating. To review changes between two versions of the same document, use the PDF comparison tool.
Watch: How to annotate a PDF online
FAQ
Each comment is written as a PDF Text annotation object with a linked Popup annotation. This is the same annotation format used by Adobe Acrobat, Preview, and other standard PDF editors. The annotations appear as sticky note icons in any compatible viewer.
Yes. The annotations are standard PDF Text annotation objects and are fully compatible with Adobe Acrobat, Foxit, Preview on macOS, and any viewer that supports PDF annotation display.
Yes. The tool reads existing Text annotations from the original PDF and displays them. When you download, both the original annotations and any new comments you added are included in the output file.
No. The PDF is loaded, rendered, and annotated entirely in the browser. No file is transmitted to any server at any point. The download is generated locally in your browser.
Yes. Use the navigation controls to move between pages and click to place comments on any page. Each comment is stored with its page number and position coordinates.
When you click a location, the tool records the canvas pixel coordinates and the canvas dimensions. On download, those values are scaled to the PDF page coordinate space to position the annotation accurately relative to the page content.
Yes. Click on an existing comment marker to edit the text or delete it. Changes take effect in the downloaded file.
Comment positions are stored relative to the original canvas dimensions and converted to PDF coordinates on export, so the position in the downloaded PDF is not affected by how the page is displayed in the browser.
Yes. Annotations are placed as coordinate-based objects in the PDF structure regardless of whether the page content is a text layer or a scanned image. The annotation position is calculated from the page dimensions, not the page content type.
A PDF comment (Text annotation) is a point-anchored sticky note that stores text in a Popup object. Markup annotations such as highlight, underline, and strikethrough are applied to a rectangular region of the page. This tool creates Text annotations, the sticky note type.
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