To change Wi-Fi network on your iPhone, tap the Settings app (the gear icon) on the home screen, tap Wi-Fi, and then select a network. Click here to see the official list of Smart TVs that support AirPlay 2.
Depending on your settings, you may see a message on the TV screen asking you to enter a password. Enter your iPhone’s unlock passcode to continue. To stop mirroring, open the Control Center, tap Screen Mirroring, and then select Stop Mirroring.
Connecting your iPhone might automatically launch iTunes and/or the Photos app on your Mac. You can close these apps if they appear.
Click the round green button at the top of the window to make the window full-screen. To stop mirroring, click the arrow again to open the menu, and then select your built-in camera and speaker from the “Camera” and “Microphone” sections.