The organisation’s billing data can be updated in the Billing tab of the Settings module. The Organisation admin should indicate the address and tax identification number for the correct calculation of VAT. Optionally, an e-mail address for sending invoices can be indicated.
Remember, without updating your billing data, it is not possible to select a plan.
Check also
How do you choose a plan?
Where can I find the invoice?
How can I resolve settlement issues?
Account 
Application