To turn on your Moto X, press the power button.
To turn off your Moto X, press and hold the power button until the Power off options window pops out.
If you fail to hold the power button long enough, the screen will be off and phone will be locked. To turn the phone off, you need unlock the phone first.
If you are unable to turn your phone off, press and hold the Power key and the Volume down key simultaneously for 10 seconds.