@JCharante 10d
Highlight the text in your dedicated PDF reading program and then after each lesson/chapter, when you sit down to review the lesson (you should be doing this even if you don't use Anki!) you can create the Anki cards manually. Creating Anki cards is really helpful for learning. I used to study at a langauge school and whenever I came across a word I didn't know, I'd quickly write it down in a notebook in the middle of class and then later in the day go back and create Anki cards for the words I had written down.
@kneebonian 10d
So sounds like more of what you are interested in is incremental reading. In the case the way you'd want to do things is copy the text to another document for the entire article then go back through determine which facts you want to keep.

Then turn it into an Anki card, preferably with clozes.

Half the benefit of Anki is making the Anki cards in the first place.

@resoluteteeth 10d
Maybe you could use some app to pull out highlights but you still need to think carefully about how to make each text chunk into a card or multiple cards (otherwise you'll waste more time than you save)

You also don't normally use an srs flashcard program like anki just when you want to review a book, you use it every day.

@siegecraft 10d
This is a common use case and many reader / annotation apps either support it natively (polarized and marginnote 3 are two that I have first hand experience with) or have third party tools available to copy annotations into anki.
@yellow_postit 10d
Check out AnkiConnect for getting things into Anki. Not sure about reader software that will call out after a highlight though.