You can add, delete and manage sub-users on your account through our Secure Client Area.
Once logged in you will want to click Billing>Manage Credit Card.
Once you are on that screen go to the Contacts/Sub-Accounts tab.
Here you can add, and delete sub-accounts and assign a variety of permissions and email options for each user.
This is helpful in many ways. You may want copies of invoices sent to an additional email, or give various users the ability to open and respond to support tickets, password resets etc.