The billing profile is edited by an organization admin in Billing, Invoices tab.
Fields: account type, legal or full name, address, city, postal code, region (required for the US), country, billing e-mail and tax number (required for a Corporate account).
Changing the tax number, country or type resets the verification of the tax number.
A complete profile is required before any top-up and any instance launch.
If in doubt, contact support.