If you’ve got an Apple TV or a smart TV with AirPlay, it’s super easy:
Make sure your iPhone and TV are on the same Wi-Fi.
Swipe down on your iPhone (top right corner) and tap Screen Mirroring.
Pick your TV from the list — and that’s it!
It should connect automatically next time if you’ve done it once. If your TV doesn’t support AirPlay, you can use a Lightning-to-HDMI adapter or apps like AirDroid or ApowerMirror.