Typically I use pen and paper, but I’ve been interested in a tablet or similar device for a while and am interested in what other people are using.
The reMarkable 2 seems like a really cool option to play with, but also pretty pricey for trying it out to see if it would even work well.
While it’s not directly related, when playing in games, I usually use a paper character sheet for reference, a notepad for consumables, story notes, and HP, and Pathbuilder on my phone for spells.
Hm, I think most tablets could probably do margin notes and color coding somehow? I’m not sure if it’s a specific program, but one of my players has her character sheet on an iPad and she colors all over it and erases it throughout the session to keep her hands busy. As a last resort you could open up the pdf in an art program and draw on top of it (which is where my mind goes since I use my tablet for art), but I would bet there are a lot of a dedicated notetaking or organizing apps that would allow it.