To turn off your iPad without using the power button, Apple has options in the General Settings menu or Control Center. Siri ...
Restarting your iPhone is usually the quickest cure for everyday annoyances, from apps freezing up to network hiccups. In fact, you should probably be restarting your iPhone more often than you think.
If your iPad says it's disabled, you'll need to connect it to iTunes or Finder to restore it. The exact steps will depend on ...