To easily add and/or remove locations from your account, select the letters inside the circle in the upper right on the Home page. The Home page is where you see the list of saved designs in the account. Then select Account Settings from the drop-down.
The account settings are split into User Information, Billing Information, Subscription, Locations, and Print History. Each section can be edited independently. In this case, select the Locations section.
To Add a location to the account click the Add Location tile. This will open a page asking for the business and billing information. Be sure to click the pink Create Location button to update the account.
Locations can also be removed from the Account Settings. To Remove a location select the 3 dots in the corner of the location you want to remove and then select Delete Location.