Apple has gradually started removing every breakable, physical button on the iPhone---like the Home button, which isn’t even a real button on the iPhone 7 and 8. There are, however, still a few physical buttons that remain: the volume buttons and the Power button.
You can obviously control your iPhone’s volume with the volume slider in the Control Center, but what do you do if the Power button is broken? Well, it’s possible to turn your iPhone off and on without it. Here’s how.
Turning Off Your iPhone
Go to Settings > General and select Shut Down. It’s at the very end.
The Slide to Power Off screen will pop up. Drag the slider to the right and your iPhone will shut down.
Turning On Your iPhone
If the Power button is broken and your iPhone is off, you can’t easily jump into the Settings app to hit a switch. Fortunately, Apple has thought of this situation.
Turning your iPhone back on is simple: just plug it in to charge over USB. Your iPhone will start up a few seconds after it starts charging (as long as the battery isn’t dead, in which case it takes longer).