How to cast my iPhone to television or other devices?

What kind of TV do you have? If it supports AirPlay 2, you can easily mirror your iPhone. Simply connect your phone and TV to the same Wi-Fi network, go to the Control Center, and tap Screen Mirroring. Your TV should appear in the list of devices. Alternatively, you can open the desired photo and click on the AirPlay icon.

If your TV doesn’t support AirPlay 2, try using mirroring apps from the App Store, like DoCast, Screen Mirroring Smart TV, or Replica. These apps work well with many TV brands. It’s important to have your iPhone and TV on the same Wi-Fi network. Download the app on your phone and follow the instructions to connect.

Another option is to connect your iPhone to your TV using a cable, which doesn’t require an internet connection - Connect iPhone to a display with a cable – Apple Support (UK)

[Edited by Moderator]

You can Mirror/AirPlay your iPhone to any other AirPlay receiver. You will find a setting on your TV if it is capable of being an AirPlay receiver, then you will need to be on the same WiFi network as your TV. Some Mac models are also an AirPlay receiver to you can share to those as well, but an iPhone or iPad is not an AirPlay receiver.

Use AirPlay to stream video or mirror the screen of your iPhone or iPad - Apple Support

Here’s some guidance to get you started→AirPlay system requirements - Apple Support