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PDF Readers & Annotation

PDF Expert, Skim, Sumatra PDF, Xournal++, GoodNotes — read and mark up PDFs.

PDFs are the universal file format nobody likes but everybody uses. The best reader / annotator depends on platform; this page covers each. For AI Q&A on PDFs see AI PDF Q&A (NotebookLM). For the academic workflow see Research & Citations (Zotero) and Document Management.

macOS

  • Preview — free; bundled; the underrated default; basic annotation; signing; reorder pages.
  • PDF Expert (Readdle) — paid (~$80 one-time, or $80/yr Pro); Mac / iPad / iPhone; the polished commercial default for Apple users.
  • Highlights — paid (~$30); Mac; export-to-Markdown / Obsidian / DEVONthink first-class.
  • ★ Skim — free OSS; macOS; the academic Mac default; great for reading papers; strong highlight export.
  • MarginNote 4 — paid (~$80+); macOS / iPad; mind-map-flavoured; visual outliner; popular with law / med students.
  • LiquidText — paid + free; Mac / iPad; gesture-based excerpting; "pull strings out of the PDF and arrange them on a canvas"; controversial price model.

Windows / Linux / cross-platform

  • Adobe Acrobat Reader — free + paid Pro; the default; bloated.
  • Foxit Reader — free + paid; lighter than Adobe.
  • ★ Sumatra PDF — free OSS; Windows; minimal; fast; reads PDF / EPUB / MOBI / CBZ / DJVU.
  • ★ Xournal++ — free OSS; Linux / Win / Mac; handwriting + PDF annotation; the FOSS GoodNotes-on-the-desktop.
  • Okular (KDE) — free OSS; Linux; full-featured.
  • Evince / GNOME Documents — free OSS; Linux; minimal.
  • MuPDF / mupdf-x11 — free OSS; minimal; ridiculously fast; CLI-friendly.
  • qpdfview — free OSS; tabbed; minimal.

iOS / iPadOS

  • GoodReader — paid (~$6); iPad classic; minimal but capable.
  • ★ GoodNotes 6 — paid + subscription; handwriting + PDF; the iPad-with-pencil default.
  • Notability — paid + subscription; same niche; audio recording while annotating.
  • Notes Plus / Nebo — paid; handwriting recognition + PDF.
  • MarginNote — see macOS.
  • PDF Expert — see macOS; same product.
  • Highlighted (Highlights iOS) — companion to Mac Highlights.

Android

  • Xodo — free + paid; cross-platform; signing; form filling.
  • Drawboard PDF — paid + free; pen-friendly.
  • Adobe Acrobat Reader — free.
  • Moon+ Reader — see reader apps; also handles PDF.

Form filling / signing (light overlap with e-sign)

  • See E-Signing — DocuSign, Documenso, BoxyHQ, etc.

Research / academic annotation

E-ink PDF reading (huge separate topic)

  • Boox / Kobo Elipsa / reMarkable / Kindle Scribe — large e-ink for PDF + stylus. See E-Reader Hardware.
  • KOReader — best PDF reflow on Kindle / Kobo / Boox; flow text out of two-column PDFs. See KOReader.

Pick this if…

  • macOS, polished, paid: PDF Expert.
  • macOS, academic, free: Skim.
  • Windows, minimal, free: Sumatra PDF.
  • Linux / cross-platform handwriting: Xournal++.
  • iPad with Pencil: GoodNotes 6.
  • Academic with Zotero: Zotero 7's built-in reader.
  • Just-want-to-read-no-annotation: Preview (Mac), Sumatra (Win), Evince (Linux).
  • AI Q&A on PDF: see NotebookLM page.

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