You can log out of your account and log back in, or you can delete the account from your system preferences.

Apple does not allow you to delete the default account on Mac. To delete the default account, you should be able to log in with an administrator account.To delete a standard account on Mac, you need to first log out of your account and then click on the Apple logo in the upper-left corner of the screen. After that, select Log Out from the drop-down menu. This will prompt you to enter your password for your admin account.

The user account will be removed from the Mac and all of its data will be deleted.

The standard account on Mac is free and it is the default account that comes with your computer. It can be used for basic tasks, but if you are looking to use more advanced features, then you will need to either create a new account or buy one of their accounts.