Uploading a receipt to your Reap Card transaction is not only a good practice to keep track of your spending, but it will also be of great help to your administrative colleagues reviewing and approving your transaction with the proof too!
Visit Dashboard → Reap Card → Transactions to view the transactions
Click on the transaction that you want to upload a receipt to open the sidebar
Click on the Upload Receipt box to upload the document
Don't forget to click the Save button to keep this change! Before saving, you may also edit the category or add a note to your Reap Card transaction.