How to highlight and annotate a PDF on your phone

1 min read·24 July 2026

Highlighting PDFs, adding notes or underlining text works slightly differently on a smartphone than on a computer. This article gives an overview per device.

Highlighting a PDF on iPhone (iOS)

Open the PDF in the Files app and tap the pencil icon (Markup). You can highlight text, add underlines, type text or draw freely. Annotations are saved in the PDF file and visible in any PDF reader.

Highlighting a PDF on Android

Android has no built-in PDF annotation editor. Google Drive and Adobe Acrobat Reader (free) are the most popular options. Open the PDF in one of these apps, tap the pencil icon and choose highlighter or text. Samsung Notes and Microsoft Edge (Android) can also annotate PDFs.

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Taking notes with a stylus

Do you have an Apple Pencil (iPad) or Samsung S Pen? You can write directly on the PDF as if on paper. In Apple Books or Files the Apple Pencil works immediately. On Samsung tablets, use Samsung Notes or Adobe Acrobat.

Exporting annotations

Want to share the PDF with annotations? Export it as a new file so the markings are baked in as a fixed layer. On iOS do this via Share → Print → Save as PDF. That way no one can accidentally remove the annotations.