Overview
Addresses are stored on a customer's account and are used when billing that customer or delivering newspapers to that customer. You can add one from the customer's action bar or directly from either the Invoice Addresses or Delivery Addresses tab. A customer can have multiple addresses, with one marked as preferred.
Before you begin
You have a customer account already created (via order/registration, the Merchant Backend, or the API).
You have the Create and update addresses permission (requires Create and update customer data).
Add the address
Open the menu item Customers and select the customer, either from the list or via search.
Open the Invoice/Delivery Addresses tab on the customer account. It shows all addresses currently on file, plus which subscriptions (if any) are linked to each one. Alternatively, from the action bar on the customer account, click Add Address → Add an invoice address/Add a delivery address, which takes you to the same form.
Click the + icon to open the new address form.

Toggle Business customer if this is a company address. This switches the form between private-person fields and company fields (e.g. Company name becomes available/required).
Toggle Private customer if this is a private address.Fill in the fields - Available fields include:
Salutation, academic title
First name, last name (and company name / additional company info, if a business address)
Street, street number, additional street info, postbox
Postcode, city, state, country
VAT number, phone number, job position
Click Save to create the address.
Optionally tick Preferred to make this the default address used automatically going forward. You can change which address is preferred at any time.

When the address is saved, it appears as a new tile in the Invoice Addresses tab. A tick icon on the tile marks it as the preferred address.
Good to know
An invoice address can be copied into a delivery address (and vice versa) using the copy icon on the address tile — useful if billing and shipping are the same.
When you edit the invoice address and want to have the changes also at the exact same delivery address (or vice versa), you can click the checkbox “Also apply these changes to the identical delivery address” - and the changes are automatically applied.
Limitation
An invoice address can only be deleted if it is not currently set as the preferred address.