How do I turn iPad Air 4th generation off?

See the following from Restart your iPad - Apple Support

How to restart an iPad that has a Home button

1. Press and hold the top button until the power off slider appears.
2. 

1. Drag the slider, then wait for 30 seconds for your device to turn off.
2. To turn your device back on, press and hold the top button until you see the Apple logo.

Can't restart?

Learn what to do if your iPad is frozen, doesn't turn on, or doesn't respond.

For a user guide, see: iPad User Guide - Apple Support

Hi FoxFifth. That article doesn’t seem to deal with the new iPad Air 4. While it uses the Fingerprint ID, it behaves as the instructions for the Face ID Pro models of iPad. I am learning new things about this thing daily.

I noticed that later and wondered. I have an iPad Air 4 on order so next time I'll have a chance of being correct. I have been avoiding iPad questions for the most part lately as my current iPad 3 with iOS 9.3.5 is so out of date that I can't check anything current.

Simultaneously press and hold the fingerprint button and the Volume up button for a couple seconds. You are then presented with the familiar “Slide to turn off” prompt.

Oh, you are in for a treat with the new iPad 😀.