The Billing pull down has tabs for Invoices, Quotes and Payment Methods.
My Invoices will list all invoices to date and the paid status. Clicking on an invoice will bring up the complete invoice and allow you to print or download as needed.
My Quotes will list all quotes you may have received for new services and status. Clicking on a quote will bring up the complete quote and allow you to print or download as needed.
Payment Methods will show you the payment method you have on your account (e.g. credit card) and allow you to add a new card and/or delete the current card on file.
The Payment Methods page also has tab on the left to take you back to your account details and other screens
