Best Apps to Write On Documents, Annotate, Edit & Collaborate
Reading a PDF without marking it up is wasted time. These are the apps US students and researchers use to actually write on documents, annotate, highlight, comment, and collaborate.
For PDFs: GoodNotes (iPad), Notability (iPad/Mac), and Readwise Reader (cross-platform) lead. PDF Expert is the heavy-duty desktop option. For Word docs: Microsoft Word's track changes and comments remain the standard, with Google Docs as the cloud alternative. For markup that syncs notes to a knowledge base, Readwise Reader → Obsidian or Notion is the modern workflow. Pencil + iPad + GoodNotes is the favorite of nursing and med students who need to annotate care plans and clinical readings.
What to look for
- Stylus support
Essential for natural annotation on tablets.
- OCR text recognition
Lets you search and edit scanned PDFs.
- Cross-device sync
Mark up on iPad, review on laptop.
- Export annotated copies
Send marked PDFs to professors or co-authors.
- Note-extraction to Notion / Obsidian
Closes the read-to-knowledge loop.
Frequently asked
What's the best free app to write on PDFs?+
Xodo (Android/Windows) and Preview (Mac) are the best free PDF annotation apps.
Can I write on PDFs on my iPad?+
Yes, GoodNotes, Notability, and PDF Expert are top choices for iPad annotation with Apple Pencil.
How do I edit a PDF document?+
Use Adobe Acrobat or PDF Expert for full editing; for annotation only, Readwise Reader or GoodNotes work.
Can I collaborate on document annotations?+
Yes, Google Docs, Notion, and Hypothes.is allow shared annotations and comments.