Open locations in your account:
There you manage addresses and set defaults. The UI labels are default shipping and default invoice.
Defaults prefill checkout for shipping and invoice. Stripe Tax uses the ship-to address. Delivery estimates use the shipping default. Buyer ship-to is currently the Netherlands and Belgium only.
Your first address can set both defaults. Later you can set default shipping and default invoice independently. There is no permanent rule that both must stay the same address.
One account can manage multiple delivery addresses and locations. That helps when you order for more than one site from the same practice account. See:
Buyer support: support@ordentic.com.