If you would like to check what e-mail address you've sent a digital receipt to afterwards, here's how to do it.
Search for the purchases receipt number in the search box at the top. If you do not have a receipt number you can press Previous Period until you arrive at the day the purchase was made.
Find the purchase in the list and press it.
Press Receipt Copy.
In the box for receipt printing you will find the e-mail you last sent the receipt to. If there is no e-mail address, this means you did not send the receipt per e-mail when the purchase was made.