When someone registers for an event using an iPhone, iPad, or Safari on their Macs, they can pay using their Apple Pay linked credit or debit card without entering the full details of their card.
Apple Pay is really more of an iOS feature; credit/debit cards are securely stored on an iOS device and authenticated using the device's thumb scanner. So, even when an attendee is using Safari on their computer, clicking the Apple Pay button will initiate a prompt on their phone asking for their thumbprint.
Once someone reaches the payment page, select the Apply Pay button.
Hold your thumb over the home button for Apple to read your thumbprint or select Pay with Passcode.
When an attendee pays via Apple Pay, the payment is still processed by Stripe, the payment processor used by Registrations. It gets the same processing fee, and the payment follows the same lifecycle that a normal credit/debit card payment would. In fact, you can think of Apple Pay as just a different method of entering a credit/debit card, especially since there are no extra fees with Apple Pay.