How do I annotate PDFs on iPhone for free?

Apple shipped free PDF annotation tools in iOS 15 and they've gotten better every year. By 2026, you don't need a paid PDF app for most annotation tasks. Here's the full toolkit.

Built-in tools:

1. Quick Look / Files (anywhere)

Tap any PDF in Files, Mail, Messages, or Safari.
Tap the markup icon (pencil tip in a circle) in the top-right.
The markup toolbar appears with:

- Pen (freehand drawing)

- Highlighter

- Pencil (rougher freehand)

- Eraser

- Lasso (select annotations to move)

- Color picker

- + button → Text, Signature, Magnifier, Shapes

Annotate, then tap Done → Save.

The annotated PDF saves over the original (or as a copy if you choose).

2. Apple Notes (best for new annotations + organization)

Open Notes → new note.
Drag and drop or paste a PDF.
Tap the PDF preview → annotation toolbar appears.
Annotate as above.
Notes also lets you handwrite alongside the PDF with Apple Pencil — useful for studying.

3. Apple Books (best for reading + highlighting long PDFs)

Save the PDF to Books (Share → Books).
Tap to read.
Long-press text → Highlight, Underline, or Add Note.
View all highlights/notes from the contents menu.

Books is better than Files for reading long PDFs because it remembers your last page and preserves a clean reading experience.

4. Preview (Mac) ↔ iCloud (cross-device)

If you annotate on Mac via Preview, your annotations sync to iPhone via iCloud Drive. Same in reverse.

Apple Pencil on iPad (handwritten annotations):

iPadOS adds Apple Pencil support for handwritten notes directly on PDFs. The handwriting is recognized as text via Scribble, so it's searchable.

Common pain points and workarounds:

Form filling: tap a form field. If it's a fillable PDF, the keyboard appears. If not, use the Text tool to overlay text. iOS doesn't auto-detect non-form-PDF fields.
Signatures: in the markup toolbar, tap + → Signature. Sign once with your finger, save, reuse.
Annotations not saving: ensure you tap Done → Save after editing. Just closing the app discards changes.
PDF too large for Quick Look (over 500 MB): use Files' built-in viewer or Books — Quick Look has a memory limit.

When to use a paid PDF app:

The built-in tools cover ~95% of annotation needs. You only need a paid app if you:

Need OCR on scanned PDFs (PDF Expert, Notability).
Need to redact (PDF Expert).
Need advanced form filling for legal/business forms.
Want a unified library across iPhone, iPad, Mac, with cloud sync (Notability, GoodNotes).

For organizing dozens or hundreds of annotated PDFs (research, contracts, manuals), a PDF organizer like Némos lets you tag, fold, search across all annotations on-device.

The 2026 verdict:

For 95% of users, free iOS tools are enough. Save the $30/year for a coffee.