Apple released iOS 8.1 — the latest update to its mobile operating system — on Monday, and with it arrived the first stage of implementation of Apple Pay, the much-anticipated mobile payment system, in the United States. iPhone 6 and iPhone 6 Plus owners will have the full range of capabilities, while users who purchase the new iPads, arriving later in the week, will also enjoy some of the functionality.

Apple Pay employs the Touch ID fingerprint recognition feature to guarantee that only authorized users can pay at enabled locations. Touch ID was introduced with the iPhone 5S last year, and is now a standard feature of Apple's latest mobile devices. Only the iPhone 6 and 6 Plus are also equipped with a near field communication (NFC) chip, which is necessary to use the smartphone as a wallet in retailers that have installed the required technology.

The iPad Air 2 and iPad Mini 3, which will go on sale on October 24, don't have the NFC chip, but the Touch ID feature will serve to make purchases through apps. Because the system links directly to users' bank accounts, they receive the same benefits, such as rewards points, that they would if they were using their credit card. At launch, major banks that have signed on include Bank of America, Citibank and Wells Fargo.

More than 220,000 retailers already have Apple Pay capabilities, including McDonald's, Walgreens and Whole Foods. By early next year, when the Apple Watch arrives with NFC and Touch ID, more than 500 banks and 250,000 retailers nationwide will have the necessary Apple support to allow mobile payment on their premises.