We want to enable screen reading for a large number of PDFs that open in iOS apps and Safari. The simple solution is to have users enable Speak Selection in iOS, which displays the Speak button when text is selected in any web context. This works for any Word DOC or HTML, but not for PDFs. I've already tried turning on "Tagged PDF" in a number of PDFs, plus tagging content in different ways, but it does not work.
I can also investigate using the iOS "Open In" functionality, but directly enabling screen reading in the web context is a better option for us. Is there a way to tag PDFs so they are screen readable?