This article explains how to turn off your iPad. Instructions apply to every model of iPad, including the original, all versions of the iPad mini, and all iPad Pros.
How to Turn iPad Pro and iPad On and Off – How to Turn Off iPad Pro
Turning off an iPad without a Home button is a little different than turning off an iPad with a Home button, but we'll explain the differences. Here's what you'll need to do:
For iPads with a Home button: Press and hold the Power/Sleep button in the upper-right corner of your iPad.
For iPads without a Home button: Press and hold the power/sleep button and the volume up or down button on the side of your iPad.