Billing and account contact information
You can view your account's contact and billing information from within the Settings tab. To do so, click on Settings and then click on the Contact information menu:
From there you can edit the information by clicking on the Edit contact information button and filling in the details. If you would like to have invoices sent to multiple email addresses, in addition to the primary contact and billing contact (which are the same by default), you can add those to the Alternate emails field.
All Administrator-level users are also listed. Note that only Admins can be selected to receive billing-related emails.