How do I opt out of e-receipts?

Once users activate e-receipts they cannot opt themselves out, but they can opt out specific PCARDs. Credit Cards can be added or opted out in the Credit Cards section of Profile.

In Profile / Profile Settings look for Credit Cards section. It will list all saved cards. Click the pencil icon to open and edit a card. Uncheck the "Receives e-receipts for this card." checkbox. Save the change.