comments:
You can get an inexpensive Blue Tooth keyboard like this one--works great, lightweight, battery rarely needs recharging. People are complaining about Apple Notes causing a lot of heating on the back of iPads as well. Take a look at the free version of OneNote, You can write or type notes, annotate PDF's import images, solve equations. It's cross platform (but a lot of people complain about how it works on android) and syncs automatically (you need to set that up). I like the way the notebook, sections, subsections, pages, and sub-pages work like a paper notebook. Apple has it's own handwriting to text tool called Scribble but it drives me nuts. I use a handwriting keyboard--I write with a stylus and it's instantly converted to text. It uses the same tech as Scribble (MyScript) but IMHO it works better, and I'm not having any overheating issues (but I don't do a lot of writing in the Notes app).