The primary address is the address a patient's orders ship to by default. It is pre-selected at checkout. For a patient who has checked out before, the first address they entered is their primary address until they change it.
At the cart or checkout step, the patient can keep the selected address, choose a different saved address for just that order, or add another address. If they will be at a new address for a while, they can make it their primary in Settings > Addresses so it is selected automatically next time.
Always confirm the selected address before the pay step. This applies to refills and to staying on the same dose, too.
