You can upload receipts in multiple ways
If you have the admin/owner role, you can upload your receipts in the accounting tab of the app
If email receipt collection is enabled, the cardholder will receive an email after every card payment to upload their receipts by following the instructions
If SMS receipt collection is enabled, a cardholder will receive a text after every card payment to upload their receipts by following the instructions
(SMS collection is only available for US/CA phone numbers)