How do I power off my iPhone?

If you have a phone with no home button then hold the volume and side power button then swipe to power of but if you need to force restart without using the touchscreen Press and quickly release the volume up button, press and quickly release the volume down button, then press and hold the side button. When the Apple logo appears, release the button.

If you have a phone with the home button then just hold the side power button and swipe to power off or to force restart without the touchscreen just hold the side power button

Hope this helps :D

The side button does both.

Hold to turn “off” (after using the slider).

Hold to turn “on”

You can also turn off the phone from Settings -> General -> Shut Down -> Slider to “off”