how to restart

How to restart your iPhone X, 11, 12, or 13

1. Press and hold either volume button and the side button until the power off slider appears.
2. Drag the slider, then wait 30 seconds for your device to turn off. If your device is frozen or unresponsive, force restart your device.
3. To turn your device back on, press and hold the side button (on the right side of your iPhone) until you see the Apple logo.

For more information see this Apple Support document: Restart your iPhone - Apple Support

If you need to turn off your phone:

Hold the “Volume Up” button and the “Sleep” button at the same time until the screen shows a “Slide to power off” option at the top of the screen.

If you need to RESTART your phone (if not frozen):

Go to settings,

General

Reset

Select any of the options that do not include resetting or deleting YOUR information that you cannot retrieve.

My usual “Go To” is Reset Network settings.

Doing this, will remove saved Wi-Fi passwords at commonly visited locations (including your office and home). So make sure you are able to retrieve those passwords from a 3rd party/source such as your router or someone you live/work with.