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How to Fix Text Highlighting Not Working in PDF on iPad
Question details
The user is unable to highlight text within a PDF file on their iPad.
- Product
- Adobe Acrobat
- Device & OS
- iPadOS
- Scenario
- Reviewing or studying a PDF document and attempting to mark important text.
- Observed behavior
- The highlighting tool does not snap to or select any text because the PDF is a scanned image lacking a selectable text layer.
Ensure you have a secondary, text-based PDF file available to test the highlighting tools in your current application.
Verify Document Type and Apply OCR
Determine if the PDF is an image-based scan and use Optical Character Recognition (OCR) to make the text selectable.
When a PDF is created from a scanner or a photograph, the text is flattened into an image. iPad PDF editors like Adobe Acrobat cannot highlight this text natively because there is no text layer for the tool to select.
Open a different PDF file that you know contains selectable text, such as a native Word document saved as a PDF.
Attempt to use the highlight tool on this second document. If it works perfectly, the issue is strictly related to your original document, not the app or the iPad.
Open the problematic, image-based PDF in a desktop PDF editor or an advanced iPad app that supports Optical Character Recognition (OCR). Run the OCR tool to extract and recognize the text layer.
Save the newly converted PDF, open it on your iPad again, and use the highlight tool to seamlessly select the now-recognized text.
Highlight and Edit Any PDF with WPS Office
WPS Office provides advanced PDF editing tools for iPad, including seamless text highlighting, annotation, and built-in OCR to instantly convert scanned images into selectable, highlightable text.
- 1. Download the App: Install WPS Office from the iPad App Store and open your problematic PDF document.
- 2. Use OCR for Scanned Files: If the document is a scan, navigate to the PDF Tools menu and select OCR to extract and recognize the text layer.
- 3. Select the Highlight Tool: Tap on the Annotation menu, select the Highlight tool, pick your preferred color, and drag across the text to mark it.
Frequently Asked Questions
Why can I highlight some PDFs on my iPad but not others?
Some PDFs are native text documents, allowing apps to recognize characters instantly. Others are flattened images or scans. Image-based PDFs require OCR (Optical Character Recognition) to extract a text layer before highlighting is possible.
Does restarting my iPad fix the PDF highlighting issue?
No, restarting the iPad will generally not fix document-specific problems like an image-based PDF. It only resolves app glitches or device memory issues.
How do I know if my PDF is a scanned image?
If you try to select a single word by long-pressing on it and a blue selection box doesn't appear, or if zooming in reveals pixelated text instead of sharp vectors, your PDF is likely a scanned image.
Can I use OCR directly on my iPad?
Yes, several premium PDF apps on the iPad App Store, including WPS Office, feature built-in OCR capabilities. Alternatively, you can run OCR on a desktop computer and transfer the selectable PDF back to your iPad.
