What simple app would you recommend for recording from OP-Z to iPad Pro (current model with USB-C)?
I want high quality recording and possibly basic editing (pretty much just trimming). I don’t want to learn how to use a DAW I just want to be able to back up ideas and live performances.
Really appreciate any help as there are so many sound/voice/audio recorders on App Store!
The built-in Voice Memos app will do this. Try that first.
Just make sure to switch it to “lossless” recording in the Settings app.
The next thing to look at is AudioShare, which is an essential music app for the iPad.
I use Audioshare for this sort of thing too.
Yeah, it’s The Best.
You will probably get some good use out of Apollo Remote Recorder, if you’re looking for another great one you can use for free. It also has some sister apps (Sound Injector, and maybe one or two others?) that are also pretty neat, and it’s legit free, not just trial and then IAP. They allow you to integrate multiple iOS, PC and/or hardware devices into your workflow together and record it all in a DAW on your computer without a big hassle. Near as I can tell, they are letting you have the iOS apps for free with the hope in mind that you will want to integrate another piece of Mac or Win10dows software that will cost money, but I haven’t investigated too deeply. I’m just enjoying the feature rich experience and inter-app connectivity through AudioBus (which is another must have for anyone trying to do more than doodle and scribble with sounds on their iPad). I hope this helps! 
This just occurred to me now, but if your iPad was restored from an earlier backup of an iPad that was pre-iOS 13(iinm), you should be able to find the Apple Music Memo app, which has since been discontinued, but still runs on iPhone/iPad of anyone who had it previously, and I thought it was an included app with the OS, like Garage Band. That is my absolute favorite “tape recorder for music” style app. Maybe see if that one is available in your iPad somewhere or in your App Store history. It uses AI to add drums and bass (if you want it) to your ideas, and has a couple other neat features. I don’t know why discontinued it? Kinda feels like when Google builds an awesome new product, and then throws it in the trash a year later 