Annotate PDF

What is Annotate PDF?

Annotate PDF lets you mark up a document directly in your browser with comments, highlights, text notes, stamps, arrows, freehand drawing and signatures. You can point out a problem, sign where indicated, or highlight a key clause, then save a flattened or layered PDF that anyone can open. The annotations are drawn onto the page in the browser, so your original document stays with you and never gets uploaded to a server. It is built for review and sign-off without the friction of a desktop suite. Reviewers can circle a figure, add a sticky comment, or stamp a document Approved in seconds. Because everything runs locally, sensitive agreements, drafts and internal memos stay private. There are no watermarks on the output and no account to create, just a fast canvas-based editor that turns any PDF into a markup surface.

Why use this tool?

Annotation happens on a canvas in your browser, so the underlying PDF and your handwritten signature never reach a server, keeping legal and personal documents confidential. You get a full markup toolkit, highlights, comments, stamps, arrows, freehand ink and signatures, without installing software or signing up, and the saved file opens in any standard PDF reader. There are no watermarks, no upload size limits beyond your device's memory, and the tool works offline once loaded. Markups render crisply at any zoom level because they are drawn as vector and image layers on the page.

Common use cases

Use Annotate PDF to review a contract and flag clauses for negotiation, sign a form that arrived by email, or give feedback on a design proof by drawing arrows and adding notes. Teams use it to stamp invoices Paid or Approved, teachers grade submitted PDFs with comments and highlights, and freelancers add a signature to an agreement before returning it. It is also useful for redlining a draft, pointing collaborators to a specific line, or quickly initialing every page of a multi-page document. Anytime you need to add visible feedback or a signature without printing, marking, and rescanning, this is the tool.

How to use Annotate PDF

1. 1Open your PDF by dragging it in or selecting it from your device
2. 2Pick a tool: highlight, comment, arrow, stamp, draw or signature
3. 3Place and adjust your annotations on the relevant pages
4. 4Add a signature by drawing, typing, or uploading an image of it
5. 5Save and download the annotated PDF

Frequently asked questions

Are my document and signature kept private?

Yes. Annotate PDF works entirely in your browser. Your PDF is loaded locally, all markups and your signature are applied on your device, and the finished file is generated client-side. Nothing, including your signature image, is uploaded or stored on a server, which is essential for contracts and confidential paperwork.

Will annotations stay in place when I open the file elsewhere?

Yes. Saved annotations are written into the PDF so they appear in any standard reader such as Acrobat, Preview or Chrome. Highlights, comments, stamps, arrows and signatures keep their position relative to the page content, so reviewers see exactly what you marked regardless of which app or device they use to open it.

Does adding annotations change the original page content?

No. Annotations are layered on top of the existing page; the original text, images and layout underneath stay intact. Highlights overlay the words without altering them, and other markups sit above the page. If you choose a flattened export, the markups become a permanent part of the page but the original content is still preserved beneath them.

How do I add my signature?

You can draw your signature with a mouse, trackpad or finger, type it and pick a style, or upload a transparent image of an existing signature. Once added, you can move and resize it, then place it on the signature line of any page. The whole process happens locally, so your signature never leaves your device.

Can I annotate PDFs on a phone or tablet?

Yes. The canvas editor supports touch, so a tablet or phone is actually great for freehand drawing and signing with your finger or a stylus. Open the PDF in a mobile browser, mark it up, and download the result. No app is needed, and the document stays on your device throughout.

Can I highlight text and add typed comments?

Yes. You can drag the highlighter over passages to emphasize them and drop text comments or sticky notes anywhere on a page. Comments can be positioned next to the content they refer to, making it easy for reviewers to follow your feedback. You can usually adjust color and size to keep different reviewers' marks distinct.

1. 1Use a flattened export when sending signed documents externally so recipients cannot move or remove your markups.
2. 2Add your signature once, then resize and reuse it across every page that needs initialing.
3. 3Pick distinct highlight colors for different review themes, such as legal, factual and stylistic notes.
4. 4Zoom in before placing arrows or signatures so they land precisely on the intended line or field.

How does it compare?

Adobe Acrobat offers the deepest annotation and form-filling features but requires a paid plan for much of it, while Smallpdf and iLovePDF provide solid online annotation that uploads your file to their servers and gates heavier use behind subscriptions. Annotate PDF keeps everything in your browser with no upload, no watermark and no account, which is ideal for private contracts and quick sign-offs. For advanced form fields, OCR or collaborative review threads, a full desktop suite still has the edge.

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