9To5Mac revealed a bunch of photos and some info on Apple Pay (more specifically, on how to set up Apple Pay and add credit card information to your device). Apple Pay is set to launch in a few more days (mostly coinciding with the new iPad).
When Apple Pay debuts on users' devices (iPhone 6, 6+, new iPads), you will have to setup Apple Pay (add cards, info, etc.) before you can start paying just by flashing your iPhone 6/6+ at the Apple Pay-enabled terminals. From the screenshots and info we have, here's how to set up Apple Pay:
You will most likely be asked to setup Apple Pay in the setup screen when you update your firmware (just like setting up iCloud or iCloud Drive). If you skip this (you can), you will still be able to add Apple Pay details later via Settings.
How to Setup Apple Pay On iPhone 6 and 6 Plus in iOS 8.1
Step #1. Open Settings.
Step #2. Tap on Passbook & Apple Pay (you'll find this under iCloud and iTunes & App Store options.)
Step #3. Next, if you are setting up Apple Pay for the first time, tap on Set up Apple Pay.
Step #4. Next, tap on Add a new Credit or Debit Card.
Step #5. Enter the card details. You can click a picture of your card, and your iPhone will scan the card for the number. Enter the rest of the details and tap on Next.
Screens also show that you will be able to set transaction defaults: info like billing address, email, phone and default card to be used whenever you pay through Apple Pay.
You will be able to add a bunch of cards to Apple Pay. As regards Passbook, it looks like you can add a maximum of 8 cards to it.
Apple has done a lot of groundwork for Apple Pay, collaborating with a lot of outlets and banks in the country. It's supposedly secure with several levels of data encryption (including a point where your real credit card data is never sent anywhere). Apple Pay will work through iPhone 6, 6+, Apple Watch (which is set to release in early 2015) and very possibly, Apple's new iPads.