Apple Pay is a digital wallet and payment service which allows you to make payments from your card using your iPhone or Apple Watch.
Apple Pay securely stores your debit card details and allows you to make contactless payments in stores by holding your smart device to a payment terminal. You can also make payments online through your hone using Apple Pay
If you use Apple Pay, your banking account will just show a regular card payments in it's recent statement.
You can set it up on any smart device with a recent version of iOS.