Top 5 Best Tools for PDF Annotation in 2025

Marking up PDFs is essential for students, researchers, and professionals who need to highlight, comment, or draw on documents. The right annotation tool can boost your productivity. Here are five top-rated options that cover every use case, from free basics to advanced collaboration.

Whether you work on Windows, macOS, iPad, or Linux, there’s a tool that fits your workflow. Most support highlights, sticky notes, freehand drawing, and text boxes. Some add cloud sync, OCR, or form filling. Choose based on your device, budget, and team needs.

1. Adobe Acrobat Reader – The Industry Standard

Adobe Acrobat Reader is free and runs on every desktop and mobile platform. It offers highlight, underline, strikeout, sticky notes, and freehand drawing. The paid Pro version adds OCR, PDF editing, and e-signatures. Best for heavy users and those needing compatibility with corporate workflows.

• Pros: Reliable, feature-rich, supports all PDF types.
• Cons: Free version lacks some advanced markup tools (e.g., text boxes require Pro).

2. Foxit PDF Editor – Lightweight and Fast

Foxit is a great alternative to Adobe. It loads quickly and has a ribbon interface similar to Microsoft Office. Annotations include highlight, comment, shapes, and freehand. The cloud version allows real-time collaboration. Recommended for teams who need to review documents together.

• Pros: Fast performance, collaborative features, good mobile apps.
• Cons: Some advanced features require a subscription.

3. Preview (Mac) – Built-in and Simple

Mac users already have Preview, which handles basic annotations like text highlights, notes, and signatures. It’s free, pre-installed, and very intuitive. For light markup (e.g., reading papers), it’s all you need. For complex drawings or form filling, consider third-party tools.

• Pros: Free, no installation, tight macOS integration.
• Cons: Limited to basic tools; no collaboration or OCR.

4. Xodo – Cross-Platform and Free

Xodo offers a clean interface with full annotation features: highlight, underline, strikeout, freehand drawing, text boxes, and sticky notes. It works in browsers, on Windows, iOS, and Android. Syncing via Google Drive, Dropbox, or OneDrive is seamless. Great for students on a budget.

• Pros: Completely free with no watermarks, intuitive UI, syncs with cloud.
• Cons: No offline editing on some platforms, limited advanced features.

5. Kami – Best for Education

Kami is designed for teachers and students. It runs as a Chrome extension or web app. Annotations include highlight, comment, shapes, and voice notes. It integrates with Google Classroom and Canvas. Ideal for schools needing to mark up PDF assignments collaboratively.

• Pros: Educational focus, voice annotations, works in browser.
• Cons: Requires internet connection; free tier has limited storage.

Choosing the best PDF annotation tool depends on your needs. Adobe and Foxit are excellent for heavy professional use, while Preview and Xodo cover basic to moderate needs at no cost. Kami is perfect for education. Try a few to see which fits your workflow.