Allowing visible annotations (writing or typing) directly on pdf upload

Hello! I love the app so far. It’s amazing, so thank you. Something that would improve the app would be to annotate the pdf document as well - making it a combination of note-taking and being able to directly make flashcards as well during a lecture. I see you have already a “notes” section on the pdf document which is wonderful. Not sure if my feedback is possible but it would be a great addition if it is. :)