'%3e%3cpath%20d='M8%200C12.4183%200%2016%203.58172%2016%208C16%2012.4183%2012.4183%2016%208%2016C3.58172%2016%200%2012.4183%200%208C0%203.58172%203.58172%200%208%200ZM11.6162%204.38379C11.2257%203.99337%2010.5927%203.99338%2010.2021%204.38379L8%206.58594L5.79785%204.38379C5.40732%203.99334%204.77429%203.99329%204.38379%204.38379C3.99331%204.77429%203.99335%205.40733%204.38379%205.79785L6.58594%208L4.38379%2010.2021C3.99348%2010.5927%203.99341%2011.2257%204.38379%2011.6162C4.77426%2012.0066%205.40734%2012.0065%205.79785%2011.6162L8%209.41406L10.2021%2011.6162C10.5927%2012.0066%2011.2257%2012.0067%2011.6162%2011.6162C12.0067%2011.2257%2012.0066%2010.5927%2011.6162%2010.2021L9.41406%208L11.6162%205.79785C12.0066%205.40735%2012.0066%204.77429%2011.6162%204.38379Z'%20fill='%23080E17'%20fill-opacity='0.46'/%3e%3c/g%3e%3cdefs%3e%3cclipPath%20id='clip0_3761_713'%3e%3crect%20width='16'%20height='16'%20fill='white'/%3e%3c/clipPath%3e%3c/defs%3e%3c/svg%3e)
How to Fix PDF Highlighting Not Working on iPad Pro
Question details
Users are unable to use the highlight tool or select text within a PDF document on an iPad Pro.
- Product
- Adobe Acrobat PDF
- Device & OS
- iPad Pro
- Scenario
- Attempting to annotate, select, or highlight specific text passages in a PDF file for studying or reviewing on an iPad Pro.
- Observed behavior
- The text selection tool fails to grab words, and the highlight tool does not work, typically because the PDF is a scanned image without recognizable text or the document is locked for editing.
Check for a lock symbol at the bottom right of the screen indicating the file is secured, and try to select a single word to confirm if the PDF contains an actual text layer or is simply a flat scanned image.
Perform Optical Character Recognition (OCR) to Make Text Selectable
If your PDF is a scanned document, you must use OCR to convert the image into readable, selectable text before the highlight tool can function.
A common reason highlighting fails is that the PDF is composed entirely of scanned images rather than typed digital text. Running OCR (Optical Character Recognition) analyzes the document and creates a hidden text layer that annotation tools can interact with.
Launch Adobe Acrobat Pro DC and open the scanned PDF document you want to highlight.
In the right-hand toolbar, click on 'Tools' and select the 'Enhance Scans' option.
In the Enhance Scans toolbar, click 'Recognize Text' and choose 'In This File'. Click the 'Settings' button to select the correct document language.
Click 'OK' on the settings dialog, then click the 'Recognize Text' button to begin processing the document.
Once the OCR process finishes, save your document. You will now be able to use the text selection and highlighting tools on your iPad Pro.
Check and Remove Document Restrictions
Determine if the document has been secured by the author, preventing any annotations or highlighting from being added.
Easily Read, Highlight, and OCR PDFs with WPS Office
WPS Office offers a comprehensive suite of PDF tools, including built-in Optical Character Recognition (OCR). You can easily convert scanned images into selectable text and seamlessly highlight important notes directly on your devices.
- 1. Open the Scanned PDF in WPS: Launch the WPS Office application and open your scanned PDF document.
- 2. Use the OCR Feature: Navigate to the PDF Tools menu and select the OCR option to extract and recognize the text in the image.
- 3. Convert the Document: Confirm the language settings and let WPS Office convert the scanned pages into a fully searchable and editable document.
- 4. Highlight Your Text: Tap on the Highlight tool from the top annotation bar and drag across the newly recognized text to apply your highlights.
Frequently Asked Questions
Why can I highlight some PDFs on my iPad but not others?
This usually happens because the problematic PDF is a flat scanned image without a readable text layer, or the document has security restrictions applied by the author that disable annotation tools.
Can I perform OCR directly on my iPad Pro?
Yes, many modern PDF editors, including WPS Office and Adobe Acrobat Premium, offer mobile OCR tools that allow you to recognize and convert scanned text directly from your iPad.
Will highlighting work if I just convert the PDF to a Word document?
Converting a scanned PDF to Word usually triggers an automatic OCR process in capable software. Once converted, the text will be editable and highlightable in a word processor, but you will be working outside the original PDF format.
Is it possible to highlight text in a secured PDF?
No, if a PDF is secured with permissions that explicitly prevent commenting and annotating, you must first unlock the document using the correct permissions password before the highlight tool becomes active.
