Make sure your iPhone and TV are connected to the same Wi-Fi network
On your iPhone, open Control Center
Tap Screen Mirroring
Select your TV from the list
Enter the AirPlay code shown on your TV if prompted
To stop mirroring, open Control Center again and tap Stop Mirroring
If your TV does not support AirPlay, connect an Apple TV or use a compatible streaming device
If needed, use an HDMI adapter and cable to connect your iPhone directly to the TV