To access you billing history:
1) Go to "My Account"
2) Access "Billing Information" and select "View More/Edit".
3) Scroll down to your "Payment History". From there you can view your invoices summary and download copies of past invoices. For invoices to be sent to additional contacts (outside the account administrator), make sure to add their contact details to the "Billing information" section" and they will receive a copy of new invoices.