Previewed at WWDC, launching in the fall.
iPhone X: Using Apple Pay With Face ID
We went through the checkout process with Apple Pay to give MacRumors readers who haven't yet had a chance to use the system a look at just how it works.
To use Apple Pay on iPhone X, you will, of course, need to have Apple Pay set up with a credit or a debit card in the Wallet app.
When you're at a store that accepts Apple Pay, the Apple Pay process is more or less the same as it was with Touch ID, but some of the gestures are different.
When you're ready to check out, press the side button on the iPhone X twice to bring up the default Apple Pay card and authenticate with Face ID. Then hold your iPhone X down to the reader to confirm payment. If you don't want to use your default card, make sure to swap it out with a tap before your iPhone is next to the card reader.
The double-click setting that opens up the Wallet app should be enabled by default, but if it's not, you can turn it on by going to Settings > Wallet > Apple Pay > and toggling on the Double-Click option. It's a feature you're going to want to have activated if you use Apple Pay a lot, because it speeds up the checkout process.
Without double-click turned on, you'll need to hold your iPhone by an NFC-equipped reader to bring up the Apple Pay interface before raising it back up to confirm with Face ID, adding another step to the process.
All in all, Apple Pay on iPhone X is essentially as quick and as easy to use Touch ID once you get used to how it works, but it will take a few payments to become accustomed to the new process if you're used to the Home button.