Apple Pay, the companys first step into the world of mobile payments and digital wallets, is likely to launch next week on 18 October.

According to a memo obtained by MacRumours, Walgreens has begun training its staff ahead of an 18 October rollout of the system. While Apple has said it expects its payment system to launch this month, it has yet to officially confirm a date.

Walgreens is one of many retailers signed up to support Apple Pay at launch, alongside McDonalds, Nike, Subway and, of course, the Apple Store. However, many notable retailers such as Pizza Hut, Best Buy and Bed, Bath & Beyond are still evaluating adding the technology, likely caught off-guard by the relatively speedy implementation and still weighing up the pros and cons of adopting the system.

Other leaked documents have revealed more details about Apple Pays workings. Users will be able to store details for up to eight credit or debit cards in Passbook for use with Apple Pay, either via an iTunes account or by using the iPhones camera to verify their details. The Passbook/Apple Pay settings have close ties to the credit card companies and banks partnered with the service, with users able to access recent transactions, contact their bank and even receive push notifications about account activity.

Apple Store employees will all be taking part in an hour of mandatory Apple Pay training over the next week, and will have access to special software aimed at troubleshooting iPhones where Apple Pay is not working correctly to determine where the problem lies.

With Apple holding a media event on 16 October rumoured to include the launch of a new iPad, it is likely final launch details for the Apple Pay system will be discussed there.