Apple is making U.S. states foot part of the bill and provide customer support for its plan to turn iPhones into digital identification cards, according to confidential documents obtained by CNBC. The company requires states to maintain the systems needed to issue and service credentials, hire project managers to respond to Apple inquiries, prominently market the new feature and push for its adoption with other government agencies, all at taxpayer expense, according to contracts signed by four states. Apple announced in June that its users could soon store state-issued identification cards in the iPhone’s Wallet app, billing it as a...