Apple Inc. unveiled the third version of the iPhone operating system, adding long-requested features such as a cut-and-paste function and giving software developers new ways to make money on their applications.

IPhone developers will be able to sell additional content, such as video-game levels or subscriptions, Scott Forstall, a senior vice president in charge of iPhone software, said at an event today at Apple’s headquarters in Cupertino, California. They also will have the ability to automatically update, or “push,” new versions to customers, he said.