But of course, testing the on a real device is better because it is a more accurate representation of the environment it will be running in once you distribute the app. Signing your app for Development allows you to build it in Xcode and directly run it on a device – be it iOS, watchOS or tvOS. The device has to be physically connected to your machine with a cable or over the network, and the app will be installed directly onto it. For this, you need a Development Certificate, along with a Development Provisioning Profile, both of which are needed to run the app on a device.