We are in the process of implementing Apple and Android Pay for our financial institution. Our institution issues out Master Card debit cards. My question is: is it a requirement to notify our customers anytime their card has been added to Apple or Android Pay. If so, what requirement or regulation does this fall under? Would an email or mailed letter suffice this requirement?

While your institution can offer the service, my understanding is that the consumer must add the card on the phone. You are not providing a new access device which would trigger additional disclosure under Reg E.

Since Apple Pay is a service, your institution should consult with bank counsel to determine what legal agreement, if any, you want to require from your customer before they can enroll their card. An internet search on "Apple Pay terms and conditions" yields several examples you can consider. Also, check with your vendor to see if they have any sample terms they can provide to get you started.

The vendor contract requires notification.