Taco Bell's app, two years in the making, isn't the first from a fast food chain. Starbucks has an app that lets their customers order ahead and is linked to their credit or debit card. Mobile and online ordering accounts for 40 percent of Domino's U.S. sales. Chipotle, Dunkin' Donuts, Jimmy Johns all have apps and Panera Bread and McDonald's are signing up with Apple Pay.