PDF Editing Issues

How to Fix Cannot Highlight Text or Change Reading Mode in PDF on iPad

John Wilson Oct 19, 2026 869 views

Question details

The user is unable to highlight text or change the reading mode when viewing a PDF document on an iPad.

How to Fix Cannot Highlight Text or Change Reading Mode in PDF on iPad

Product: PDF Reader/Editor
Device & OS: iPadOS
Scenario: Attempting to read and annotate a PDF file on an iPad device.
Observed behavior: The text highlighting function is unresponsive or disabled, and the app displays an error or fails to switch out of Reading Mode.

Before you start

Ensure your iPadOS and your PDF application are updated to the latest versions. Open a different PDF file to verify if the highlighting issue affects all documents or just one specific file.

Solution 1Recommended

Exit Reading Mode to Re-enable Annotation Tools

Reading Mode is designed for a clean, distraction-free viewing experience and often hides or disables editing and annotation tools like the text highlighter.

When a PDF is opened in Reading Mode, the primary interface elements are minimized to maximize screen space for the document itself. Because of this, active editing features are temporarily suspended.

Reveal the toolbars

Tap anywhere on the center of your iPad screen to bring up the hidden top and bottom navigation bars in your PDF app.

Exit Reading Mode

Locate the 'Reading Mode' or 'View' icon (often represented by a book or full-screen icon) in the top menu bar and tap it to toggle back to standard editing mode.

Access the Highlight tool

Once the standard toolbars are visible, navigate to the 'Annotate' or 'Tools' tab, select the Highlighter icon, and drag your finger or Apple Pencil across the text.

Exit Reading Mode to Re-enable Annotation Tools

Mode Switched Successfully: Your toolbars should now be visible and the highlighting function fully responsive.

Solution 2

Check and Remove Document Editing Restrictions

If the PDF is secured with a permissions password, features like copying, editing, and highlighting will be permanently locked out regardless of the viewing mode.

Advanced PDF Tools

Easily Read and Annotate PDFs with WPS Office for iPad

WPS Office offers a fully optimized PDF reading and annotation experience for iPadOS users. You can seamlessly switch between distraction-free reading and powerful editing modes, easily highlight text, and manage document permissions without hassle.

1. Open your PDF: Launch WPS Office on your iPad and select the PDF file you wish to read and annotate from your file manager.
2. Access the Annotation Tools: Tap the screen to reveal the top menu, then tap the 'Tools' icon and select the 'Annotation' tab.
3. Select the Highlighter: Choose the Highlighter tool from the toolbar and select your preferred highlight color.
4. Highlight text easily: Drag your finger or Apple Pencil over the desired text to apply the highlight seamlessly.

Effortlessly toggle between Reading Mode and Editing Mode with a single tapComprehensive PDF annotation tools including highlighters, underlines, and freehand drawingFully compatible with standard Adobe PDF formats and Microsoft Office file typesIntuitive and lightweight interface perfectly optimized for iPad and Apple Pencil

microsoft office alternative - wps office

Frequently Asked Questions

Why is the highlighter tool greyed out on my PDF?

The highlighter tool usually becomes greyed out when the PDF document is protected by security restrictions that forbid editing and commenting. It can also happen if the app is currently in a strict reading mode that temporarily disables markup tools.

Can I highlight text in a scanned PDF on my iPad?

Standard text highlighters require recognizable, selectable text. If your PDF is a scanned image, standard highlighters won't work. You will either need to use an OCR (Optical Character Recognition) tool to make the text selectable first, or use a freehand drawing tool to mark over the image manually.

How do I know if my PDF has editing restrictions?

You can usually identify restricted PDFs by looking for a padlock icon near the file name at the top of the screen. Additionally, if you navigate to the document's 'Properties' or 'Security' settings, it will list which actions (like commenting, printing, or editing) are explicitly 'Not Allowed'.

Does WPS Office for iPad support Apple Pencil for PDF highlighting?

Yes, WPS Office for iPad fully supports the Apple Pencil. You can use it for precise text selection, highlighting, and freehand drawing within your PDF documents.

PDF Troubleshooting