The materials, apparently shared by a "reliable source," show that Apple Pay can be set up either in Passbook or in a new Settings tab called Passbook & Apple Pay. Either way,it seems cards will be added using your iTunes account or by taking pictures of your card to scan in the details.
Interestingly, it seems that—if these leaks are accurate—Apple Pay will offer some fairly deep integration with than banks associated with each card. Some of the screenshots provided to 9to5mac suggest that, for each connected card, you'll be able to see recent transactions, contact the bank directly, receive push notifications, download the bank's app and more.
Perhaps on of the neatest features mentioned in this report is that Apple Pay will automatically update your cards with the banks when they expire. In other words, you won't need to delete and re-add the cards; they'll just get push notifications from the bank to tell them they've been updated.
The report suggests that Apple has already started using Pay at Cupertino, with these screenshots seemingly coming from staff at the company's Caffe Macs restaurant. It also explains that Apple had already started informing some of its staff how the system will work in Apple Stores, too:
According to the training materials, a customer who wants to return an item can simply touch their iPhone 6 or iPhone 6 Plus against the Apple Store EasyPay machine to populate their recent transaction history in the store... customers will not be required to provide their name or email address at checkout to receive a receipt, unless they're buying a service like AppleCare.
While we can't be sure if this is how Apple Pay will definitely shape up in reality, we perhaps don't have long to to wait. With an Apple event on the 16th and previous reports claiming that Pay will become available on the 18th, the finer details can't be too far away. [9to5mac]