How to highlight and annotate a PDF on iPhone

Before you begin

Keep the source document when you need an unmarked copy. Text highlighting depends on selectable text; a scanned image may require a drawing or text annotation instead.

Step by step

1. Open the PDF and navigate to the page you want to mark.
2. Select a highlight, drawing or text tool and choose its appearance.
3. Add the annotation without covering essential content.
4. Save and reopen the document to check the result.

Check the result

Review annotation placement at normal reading size. If you share the file, open the exported copy too, since that is what the recipient will see.

Limits and troubleshooting

Adding a note is not the same as editing the original paragraph. A dark rectangle or drawing over sensitive text is also not secure redaction: the underlying content may remain in the PDF. Use a proper redaction workflow for that purpose.