I can not get my xbox one elite series 2 controller to connect to my iPhone 8 or iPad Air (2013).

Hello,

See this:

If you can't connect a Bluetooth accessory to your iPhone, iPad, or iPod touch - Apple Support

Good luck.

That’s because it isn’t compatible with iOS until Apple whitelists it’s model number. This could happen soon or not at all. It suks, I know. I’ve had the Elite Series 2 since the day it released and I was bummed when I got home and seen that my iPad Pro wouldn’t recognize it. It will connect to my Android devices, but not Apple. For now, only the regular Xbox One controller works with iOS.