Receipt collection for Amazon Web Services
Cardboard automates the collection of receipts for payments made through Cardboard, so you don't have to collect the receipts yourself.
Receipt collection with email
Open the Billing and Cost Management console, choose Payment preferences, and click Edit in Default payment preferences. Enter the address under Billing contact email and choose Save changes. For card payments, add a billing alternate contact in the account settings.
Read the guide on configuring billing emails Amazon Web Services