All invoices and past payments are accessible under Account->Billing.
On this page you will see all your past invoices and their status (paid/unpaid).
Send invoices by email
You can choose to enable new invoices notifications by entering email address under Billing Information
Note that sending invoices by email doesn’t save you from checking account and paying invoices.
This type of notification is for information only and not receiving the email or adding a wrong email address does not relieve you from any contractual obligations.