To update your billing information, go to Control Panel -> Update profile -> Billing Address. Or simply use this link.

From this page, you can update all information including company name, address, VAT ID, etc. Any changes will also be reflected on your invoices/statements (past and future). 
 
Alternatively, you can edit your billing information on the Order Summary page when submitting a new project via the project Wizard.

Where can I find my invoices?

Where can I find my financial statements?