If you’re looking to make iPhone videos full screen on Imovie, there are a few things you can do to help. First, make sure that your device is set up to take advantage of the “full screen” mode. This is found under the “Settings” menu in your iPhone’s main interface. Second, make sure that your video player is set up to play videos in full screen mode. Third, if you’re using an iPad or other device with a touch screen, make sure that it’s set up to take advantage of the “full screen” mode as well. Finally, be sure to add some music and sound effects to your videos in order to give them a more immersive experience.