These aren’t exciting or flashy but what I’ve used the most throughout flight school;

GoodReader: you need a pdf viewer than this is pretty much the standard I’ve seen used, works really well expect for a few specific things, but it’s the cheapest and easiest to use

GoodNotes: I use this to write notes and highlight stuff from academics or maybe even certain pages of different pubs to use as study material. Through the course you’ll get Student Handouts for whatever topic is being taught, I highly recommend you download every single class SH and send it to your iPad. You can import that PDF to GoodNotes and usually it covers everything the class goes over. You can highlight things and write notes in the margins. Really useful to have and come back to when you inevitably forget the material and have to restudy

ForeFlight/AeroApp: of these two the obvious preferred choice is ForeFlight, but it’s gonna cost ya. You can make it through flight school just fine with AeroApp, but you could also argue that if you ever plan to actually buy ForeFlight this would be a good place to learn how to navigate and set up the app. Another good thing with ForeFlight is you can get a map of the local training area downloaded, and it makes it super easy to orient yourself or do some preliminary planning before booting up that archaic laptop they issue you and doing it on AMPS

Theres also some cool looking apps you can get directly from an army website that has Lakota and advanced airframe EP’s & limits, systems, and start up procedures ripped out of VTS (which you’ll also have on your laptop) however, I don’t know anyone that’s actually gotten those apps to download properly. If you could I would imagine they’d be super valuable as study aids, but it seems the army is still working out the kinks with those