On the practical front:
Get him used to having money at spaced out intervals. If he's used to getting, say, a weekly allowance, rearrange so it's monthly (or less). Student loans happen termly and it's a big shock to the system for students who have only had to hold out from week to week previously.
Similarly, get him used to having to pay any 'big' bills himself. His phone, for example - if you currently pay for it, rearrange things so he has to deal with that.
He does his own laundry from now on. You can teach him how everything works, but he does it himself or it doesn't get done.
Food-wise, if he'll be self-catering then I generally think they need to be able to cook three things. Pasta and sauce, say. A stir fry. That kind of stuff. Things he can alternate and tweak until he gets bored and then he can learn some more stuff.
Driving is irrelevant but if he doesn't have experience of taking public transport by himself in an unfamiliar place, then ideally it would be good for him to practice this. (Even better if it's possible for him to stay overnight somewhere away from home, although obviously covid complicates that).
With appointments, very often young people get a bit freaked out about having to make them because they literally don't know how, if they've never had to do it. Also it tends to be done over the phone which often isn't their preferred way of dealing with things. So to begin with, don't worry about getting him to remember to make appointments, but when one needs to happen, get him to arrange it. Talk him through what they're likely to ask when he calls, and sit with him (or nearby, of he'd rather you weren't listening) while he makes the call, in case he needs any help with it.
It's not too late, this is a great time to be thinking about this stuff. You would be genuinely amazed at how many parents just... don't seem to consider it.