To highlight, underline, or strikethrough text:
Open a PDF in the A1 PDF Editor app.
Tap the Annotate tool (pen icon) in the top toolbar.
Choose the tool you want:
Highlight – to mark important text in yellow or other colors.
Underline – to emphasize text with a line below.
Strikethrough – to indicate text that should be removed or revised.
Tap and drag over the text you want to annotate.
To remove the annotation, long tap the text and select Clear in a pop-up menu
Customize your annotations:
Tap on the highlighted/underlined/struck-through text to:
Change the color
Adjust opacity
Delete or comment on the annotation
Bonus Tip:
You can also use the Apple Pencil or finger for precision highlighting on iPad, and long-press to quickly switch annotation tools.
A1 PDF Editor helps you stay productive and organized—whether you're reviewing contracts, reading eBooks, or preparing academic notes.
Need more help? Explore other features like editing text, merging PDFs, or adding e-signatures right from the app.