Soft reset for iPad Air 2

Hold down both the Home and sleep/wake buttons simultaneously until your iPad goes to black and restarts with Apple logo, then release the buttons?

Good Luck!

If you go to Settings > General > Shut Down, you can turn your iPad off, then press the power button until. you see the Apple logo.

Or you can follow this:

Restart your iPad - Apple Support

If you wind up needing to do a forced reset, just hold the power and home buttons until you see the apple logo