Ps4 account data?

I once gave someone my account data and no longer want them to have them, how can I deregister them from my account (so that they can no longer enter)?

Just change the mail or password. Otherwise you can't exclude him.

I did that, does he have to enter the new data first so that he can access again? So he has no access to the account anymore?

You can also just go to the settings and then believe privacy there you can enter a pin, for example triangle square R1 R2

Change Password. If he tries to log in to you again soon, he will not be able to do it. Since you have to re-enter a changed password over and over again, even if you may have saved the account, and since he will certainly not get it, he can no longer do anything with your account. Changing the password is sufficient.