Restarting your iPhone is usually straightforward, but it gets a bit trickier if you don't have a working power button.

How To Restart An Iphone Using Power Button To restart an iPhone 10 or later, hold either volume button and the power button simultaneously and, once the option appears, slide to power off.

Quick Answer: To restart your iPhone without the power button, go to Settings > General > Shut Down, then slide to power off.