Help Center › iPhone & iPad › Annotate
Highlight, underline and strikethrough text
Mark up existing text in a PDF with highlights, underlines, strikethroughs and squiggly lines.
Applies to iOS / iPadOS 16 or later
Markup tools let you annotate text that is already in the PDF — select a word, sentence or paragraph and apply a highlight or underline in one tap.
Apply a highlight
- Tap the tool group button in the middle of the top bar and choose Markup.
- Tap Highlight in the tool dock.
- Drag your finger across the words you want to mark. The highlight follows the text and is added when you lift your finger.
- Tap one of the colours in the Properties bar to change the colour for the next highlights.
1234Markup group, the Highlight tool and a highlighted sentence
Other markup tools
All markup tools work the same way — select the tool, drag across text:
| Tool | What it does |
|---|---|
| Highlight | Fills behind the text with a semi-transparent colour |
| Underline | Draws a solid line below the text |
| Strikethrough | Draws a line through the middle of the text |
| Squiggly | Draws a wavy underline (often used for spelling corrections) |
Change colour and opacity
With the Select tool, tap the markup to select it. Pick a colour in the Properties bar, use the opacity value (40 % by default for highlights) or tap for the full panel.
Delete a markup
Select it, then tap Delete in the action bar (mobile) or press the Delete key (desktop).
Markup annotations are saved as standard PDF highlight/underline annotations and will be visible in Adobe Acrobat, Preview and other PDF apps.