By "ppl", if you mean "wizards" on your account, you can delete wizards on the login page when you enter to play the game. Click on the wizard that you want to remove, and instead of "play", you would click on "delete".
If you mean a "sub-account" on your family account, you can't delete it. Here is a link that shows info about adding sub-accounts, and it specifically says that once an account is added, it can't be removed:
Unless it's changed recently, there's no way to remove a sub-account from the main account. All you can do is set the sub-account to "Trial" so you don't get charged for it, and transfer Crowns from that account to others.
