Getting Apple Pay to Order a New iPhone
My wife wants to order a new iPhone and use Apple Pay, however, she has not applied yet. Does she need to get Apple Pay first to use it for the purchase or can she ask to use Apple Pay during ordering?
Assuming you mean the Apple Card, you can apply online here if you want to get it to make monthly payments on a new Apple product: https://support.apple.com/en-us/HT211156