iPhone, iOS 8, an app that provides a Share or Action extension A long-standing complaint about iOS is the tight degree of control Apple exercises over what apps are able to do. Those restrictions have been relaxed in iOS 8 to allow apps to extend the system’s capabilities in carefully defined ways. This means you aren’t reliant on Apple adding support for a particular social network to be able to share something directly to it, and kludgy workarounds such as special bookmarklets that send a web page to an online service are no longer necessary.
Extensions enable photo-editing apps to make filters and tools available within the Camera and Photos apps. Information from apps can be displayed in widgets in Notification Center’s Today panel,