If you are unable to select or highlight specific text in a PDF document in Adobe Acrobat Reader on Windows, this post will help you fix it.

You can easily highlight a PDF on a Mac when you open the file with Preview. To highlight text with your desired colors, use the markup tools found at the top of the program window. Highlighting ...

If you want to extract highlighted text from PDF file as a plain text file, then this post covers some good free PDF Highlight Extractor software to do that.

Need to edit a PDF document but don’t want to pay for the more expensive Adobe editors? You can add text to and sign a PDF with just the free Reader program.

To see alt text in a completed PDF document, you'll need to use a screen reading app, which is an accessibility tool for visually impaired users.