As hundreds of fans pocket new iPhone 6 models Friday, consumers will peer at their mobile screens and soon discover a new function: Apple Pay. Forget clumsily handing over cash or even signing a credit or debit card slip. With major companies including Citi and McDonald's attached to the new Apple Pay platform, many industries will be watching to see if Apple mobile consumers will embrace the new e-wallet technology, which enables swift purchases with the swipe of an iPhone or Apple Watch.