Control your home remotely with iPhone
In the Home app , you can control your accessories even when you’re away from home. To do so, you need a home hub, a device such as Apple TV (4th generation or later), a HomePod, or an iPad (with iOS 10.3 or later) that you leave at home. You must be signed in to iCloud using the same Apple ID on your home hub device and your iPhone.
Go to Settings > [your name] > iCloud, then turn on Home.
Make sure you’re signed in using the same Apple ID on all the devices.