Best PDF Annotation Tools Compared (2026)

PDF annotation tools range from free desktop readers to dedicated tablet apps with handwriting support. The best choice depends on your platform, use case (professional review vs. studying vs. lightweight markup), and whether you need annotations to sync across devices.

Quick Comparison Table

Tool	Platform	Price	Best For
Adobe Acrobat Reader	Win/Mac/iOS/Android	Free	Professional review, broadest compatibility
Foxit PDF Reader	Win/Mac/iOS/Android	Free (Pro paid)	Business teams, Acrobat alternative
Apple Preview	Mac only	Free (built-in)	Quick Mac annotation, no install needed
GoodNotes 5	iOS/iPadOS/Mac	$9.99 one-time	Handwriting, Apple Pencil, students
Notability	iOS/iPadOS/Mac	Free + subscription	Lecture notes, audio recording alongside annotations
Xodo	iOS/Android/Web	Free	Android tablet annotation, cross-platform
PDF Expert	iOS/Mac	$79.99/yr	Power users on Apple devices
Kami	Web (Chrome extension)	Free + paid tiers	Students, Google Classroom integration
OnlinePDFEdits	Web	Free	Quick browser-based markup, no install

Adobe Acrobat Reader — Best Overall Free Tool

Platforms: Windows, Mac, iOS, Android

What it does well:

• The most complete annotation toolkit in the free tier: highlight (multiple colors), sticky notes, strikethrough, underline, squiggly underline, freehand drawing, shapes, arrows, stamps, text callouts
• Annotations are fully PDF-standard and viewable in any other PDF reader
• Comment panel shows all annotations in a list with reviewer names and timestamps
• Shared Review feature for team collaboration (requires Adobe account)
• PDF form filling and signatures built in

Limitations:

• Free version requires an Adobe account to sync across devices
• UI feels dated compared to modern alternatives
• Not ideal for handwriting-heavy workflows — drawing tools are basic

Best for: Anyone who needs professional-grade annotations with maximum compatibility. The reference implementation for PDF annotation.

Foxit PDF Reader — Best Acrobat Alternative for Business

Platforms: Windows, Mac, iOS, Android

What it does well:

• Feature-complete annotation suite: highlight, notes, markup tools, stamps, drawing
• ConnectedPDF collaboration: annotate shared PDFs with team members synced in real-time
• Annotation summary export for review workflows
• Lightweight and fast — notably quicker than Acrobat on lower-end hardware
• Good OCR integration (in Foxit PDF Editor, the paid version)

Limitations:

• ConnectedPDF collaboration requires Foxit accounts for all reviewers
• Free version shows ads and upsells to Foxit PDF Editor
• Some advanced features (redaction, Bates numbering, form creation) are paid-only

Best for: Organizations looking for an Acrobat replacement with similar features at lower cost. Windows-heavy businesses especially.

Pricing: Free base; Foxit PDF Editor Pro at $179/year for advanced features.

Apple Preview — Best for Quick Mac Annotation

Platforms: Mac only

What it does well:

• Built into macOS — no installation needed
• Fast to open and use for quick markup
• Text highlight, underline, strikethrough, sticky notes, shapes, arrows, freehand drawing
• Text box and signature tool
• Excellent Apple Pencil support on Mac with appropriate hardware
• Annotates without creating an account or connecting to the internet

Limitations:

• Mac-only — no Windows, no mobile (iOS has its own Markup tool which is different)
• Less annotation management than Acrobat — no comment summary, no filter by reviewer
• No collaboration or sync features
• Some annotation types don't display correctly in Acrobat (Preview uses PDF-standard annotations, but rendering may vary slightly)

Best for: Mac users who need quick annotations without opening a heavy app. Best for personal use, not team workflows.

GoodNotes 5 — Best for Handwriting and Apple Pencil

Platforms: iOS, iPadOS, Mac

What it does well:

• Exceptional handwriting annotation with Apple Pencil — the closest to writing on paper
• Import PDFs and annotate with ink, highlighter, text, shapes, and stickers
• Annotated PDFs export cleanly with embedded annotations
• Handwriting search: find words in your own handwritten notes
• Templates and notebook organization for students
• Cross-device sync via iCloud

Limitations:

• Apple ecosystem only — no Android, no Windows
• Primarily a notebook app — PDF annotation is a feature, not the core focus
• One-time purchase but limited cloud sync without Apple devices

Best for: Students and academics on iPad with Apple Pencil; anyone who prefers handwriting over typing for annotations.

Pricing: $9.99 one-time (may have changed — check App Store).

Notability — Best for Students with Audio

Platforms: iOS, iPadOS, Mac

What it does well:

• Import PDFs and annotate alongside typed or handwritten notes
• Audio recording synced with annotations — tap a note to hear what was being said when you wrote it (lecture recording)
• Multi-note: view two documents side-by-side
• Clean, simple interface
• iCloud sync across Apple devices

Limitations:

• Apple ecosystem only
• Subscription required for full features after a free tier
• More oriented toward note-taking than document review workflows
• Less powerful PDF-specific markup than Acrobat

Best for: Students annotating lecture slides and textbooks, especially when recording lectures simultaneously.

Pricing: Free (limited); Notability+ subscription for full features.

Xodo — Best Free Cross-Platform Mobile Option

Platforms: iOS, Android, Web, Windows (UWP)

What it does well:

• Free with no meaningful limitations — unlike Adobe Reader which has more aggressive upsells
• Works on both iOS and Android — the best annotation tool that covers both
• Highlight, sticky notes, stamps, freehand drawing, text, shapes
• Real-time collaboration: share a link, multiple people annotate the same PDF simultaneously
• OCR on scanned PDFs
• Good tablet experience on Android tablets (excellent for Samsung Galaxy Tab with S Pen)

Limitations:

• UI is functional but not as polished as GoodNotes or PDF Expert
• Web version is less capable than the mobile apps
• Fewer professional document management features than Acrobat

Best for: Android tablet users; cross-platform teams where members use both iOS and Android; anyone who wants a full-featured free annotation tool without Adobe's ecosystem lock-in.

PDF Expert — Best Premium Tool for Apple Devices

Platforms: iOS, iPadOS, Mac

What it does well:

• Fast and polished — widely considered the best PDF app on iOS
• Full annotation suite plus direct text editing (edit existing PDF text)
• Sidebar annotation view, annotation search and filtering
• Link and highlight multiple annotation types
• Excellent rendering quality
• Document linking and cross-document navigation

Limitations:

• Subscription pricing is significant for an individual
• Apple only — not available on Windows or Android
• Some features (OCR, form creation) require the higher-tier subscription

Best for: Power users on Apple devices who need both annotation and editing capabilities. Common choice for lawyers, consultants, and academics on iPad Pro.

Pricing: ~$79.99/year.

Kami — Best for Education and Google Classroom

Platforms: Web (Chrome extension), Chrome OS, Google Classroom integration

What it does well:

• Deep Google Classroom integration — teachers can assign annotated PDFs to students
• Students submit annotated versions directly through Classroom
• Text, highlight, drawing, shapes, text-to-speech for accessibility
• Teacher can see all student submissions side-by-side
• Collaborative annotation: whole class can annotate the same document together

Limitations:

• Primarily web-based — requires Chrome browser or Chrome OS for best experience
• Free tier is limited; school/district licenses needed for full features
• Not designed for professional document review workflows

Best for: K-12 and higher education. If you're a teacher distributing PDFs for student annotation and collecting them back, Kami integrates more smoothly with Google Classroom than any other option.

OnlinePDFEdits — Best No-Install Browser Option

Platform: Web (any browser)

What it does well:

• No download, no account required for basic use
• Highlight, add text, draw, add signatures — all in the browser
• Works on any device with a browser (Windows, Mac, iOS, Android, Chromebook)
• Good for one-off annotations when you don't want to install anything

Best for: Quick annotations on a device without PDF software; users who need to annotate occasionally rather than regularly. Visit OnlinePDFEdits to start.

Choosing the Right Tool

For professional document review on desktop: Adobe Acrobat Reader (free) — most compatible, most complete.

For Apple Pencil / handwriting-heavy use: GoodNotes (students) or PDF Expert (professionals).

For Android tablets: Xodo — the best free option that works well with S Pen and similar styluses.

For teams needing real-time collaboration: Adobe Acrobat with Document Cloud, or Xodo's live collaboration feature.

For Google Classroom and education: Kami.

For quick one-off annotations with no setup: Browser + OnlinePDFEdits or Preview on Mac.

For heavy business use on Windows without Acrobat: Foxit PDF Reader/Editor.