evidence: Continuity Camera works wired or wirelessly. To keep your iPhone charged while in use, plug it into your Mac or a USB charger. Your Mac will notify you if iPhone battery level gets low. [...] Open FaceTime or another app to use with your iPhone camera. If the app doesn't automatically begin using it, choose your iPhone camera from the app's video menu, camera menu, or other setting. For example, in FaceTime your iPhone camera is available from the Video menu.