PDF Editing Issues

How to Highlight and Underline Text in Adobe Acrobat on iPad

Camila Milosovich Oct 19, 2026 868 views

Question details

The user is unable to highlight or underline text in Adobe Acrobat on an iPad due to text detection failures following a recent app update.

How to Highlight and Underline Text in Adobe Acrobat on iPad

Product: Adobe Acrobat
Device & OS: iPadOS
Scenario: Annotating a PDF document on an iPad.
Observed behavior: Text detection stops working, preventing the user from selecting text and applying highlights, underlines, and other standard annotations.

Before you start

Verify that your PDF is a text-based document and not a flattened image or scanned file. If it is a scanned document, you will need to apply Optical Character Recognition (OCR) before the text can be detected and highlighted.

Solution 1Recommended

Use Commenting Tools with the Magnifying Glass

Manually select text using the magnifying glass feature in commenting mode to bypass auto-detection issues.

When standard text detection fails, you can force the app to recognize your selection by utilizing the magnifying glass feature within the commenting tools. This provides greater precision when marking up documents on a touch screen.

Open Commenting Mode

Open your PDF document in Adobe Acrobat on your iPad and tap the Commenting Tools button to enter the annotation workspace.

Select the Highlight Tool

Tap the Highlight or Underline tool from the top annotation toolbar to activate it.

Long-press to Select

Long-press your finger or Apple Pencil at the beginning of the text you want to annotate until the magnifying glass appears on the screen.

Drag to Annotate

Carefully drag the selection handle across the sentence to apply the highlight or underline to the specific text.

Use Commenting Tools with the Magnifying Glass

Precision Selection: Using the magnifying glass not only bypasses the update bug but also helps you select exactly the characters you need without accidentally highlighting adjacent words.

Solution 2

Annotate Outside of Commenting Mode

Quickly highlight or underline text via the context menu without explicitly entering commenting mode first.

Easy PDF Annotation Alternative

Highlight and Underline PDFs Effortlessly with WPS Office

If Adobe Acrobat updates are causing persistent text detection issues on your iPad, try WPS Office. It features a reliable, free, and intuitive PDF reader and editor that makes highlighting, underlining, and annotating documents incredibly easy on any device.

1. Open PDF in WPS Office: Launch the WPS Office app on your iPad and open the PDF document you want to edit.
2. Access Annotation Tools: Tap on the 'Annotation' or 'Edit' tab located in the top menu bar to reveal the markup tools.
3. Select Highlight or Underline: Choose the Highlight or Underline tool, pick your preferred color from the palette, and simply drag over the text to apply it instantly.

Reliable text detection for precise highlighting, underlining, and drawing.Fully compatible with standard PDF files, as well as Microsoft Word, Excel, and PowerPoint formats.Lightweight application that runs smoothly on iPads without draining battery.Free to use with an intuitive, user-friendly interface for quick annotations.

microsoft office alternative - wps office

Frequently Asked Questions

Why can't I highlight text in my PDF on my iPad?

This usually happens if the PDF is a scanned image rather than a text-based document, or if a recent app update has caused a bug in the text detection engine. You may need to use OCR (Optical Character Recognition) software to convert the image into selectable text first.

How do I remove a highlight or underline in Adobe Acrobat on iPad?

Tap directly on the highlighted or underlined text to select the annotation, then tap the 'Delete' or 'Trash' icon from the pop-up menu that appears to remove it.

Can I change the highlight color in Adobe Acrobat?

Yes. Tap on the Highlight tool in the commenting toolbar, then tap the color palette icon to select a different color or adjust the opacity before highlighting your text. You can also tap an existing highlight to change its color.

PDF Troubleshooting