Is Apple Pay secure?
To register your card to Apple Pay on your device, you'll need to pass a number of authentication and validation checks. For each transaction you'll need to provide biometric confirmation (through fingerprint recognition) or enter a 6-digit passcode. If you're paying with an Apple Watch, you can only make payments if the watch is attached to your wrist.
If you add another person’s fingerprint to your device or share your passcode with them, they will be able to unlock your device and make payments. Do not add additional fingerprints or passcodes if you do not wish them to use your Apple Pay to make payments. If you choose to do so you could be breaking your security obligations and the liability for any unauthorised or incorrect payments may sit with you.
Your card data is also encrypted and not shared with Apple.