I've been learning FL Studio and I'd recommend it for starting because it has a pretty good free version to try out (the limitation is that while you can save files, you can't reopen them without a licence). I since bought it since it's a lifetime licence rather than a subscription.
I would say that it's got a good layout that makes sense, but definitely seek out a tutorial or at least demo of the features to familiarise yourself. It's well designed but there's a lot going on, it's easy to get lost when it's all new.
For even simpler stuff beepbox.co is a very usable browser based thing with a surprisingly rich feature set. Extremely easy to bang out some riffs and play with the instruments but still end up with a real ass song. This is what I've been using to make the songs for cover games, I just export straight from it. Definitely good for if you just wanna noodle around practicing beats, I do it as quick practice now and then.
That said its a bit harder on mobile. If someone wants to recommend me an android based way of banging out some music, I'd love to hear it while I'm on a trip and only on little screen.

