Press and hold the top button and either volume button until the power off slider appears
Drag the slider to turn off the iPad
If the iPad has a Home button, press and hold the top button until the power off slider appears
Drag the slider to turn off the iPad
If the screen is unresponsive, press and quickly release the volume up button, then the volume down button, then press and hold the top button until the Apple logo appears and the device restarts