An Account Owner is a special type of an Administrator.
Administrators have access to account settings, such as billing. Access Billing from the drop-down under your name in the top right-hand corner of the application.
One of the settings is an Account Owner, which is found in the lower right-hand side of the Billing page.
While users can be removed from an account, the Account Owner cannot be deleted. If you need to, you can change the Owner to any one of the Administrators. The Owner feature is a safe-guard so you don’t accidentally delete administrators if they leave or change jobs.
Also, the Account Owner is the administrator who gets a copy of the monthly invoice. But each Administrator can see billing history from the Billing page.