Best quick recorder for guitar riffs?

Hi, my partner has been coming up with loads of ideas for riffs to the point that he is forgetting some. I want to get him something he can record easily direct from guitar to capture the ideas easily when his whole rig isn't booted up. He has an android phone (but works on Mac/logic/kemper).

Is there something that works like a Dictaphone but with direct input from a guitar cable? Needs to be very simple to use and not gimmicky as he doesn't normally like gadgets and if it's any sort of faff he'll say what's the point, he may as well not up the computer!

Does such a thing exist, for plug, play, capture and playback?!