iPad + Notability app. This is how read PDFs, whether research papers or books. Except not able to flip back and forth like with printed copy, it allows me to w

iPad + Notability app. This is how read PDFs, whether research papers or books. Except not able to flip back and forth like with printed copy, it allows me to write notes, highlight, underline. I wish Apple new app Freeform had ability to import PDF, but it only inserts a shortcut to PDF file, pretty much useless for my note taking/reading purposes.