My iPad Air won’t update to iOS 13

Okay,

That confirms you have an iPad Air 2.

If your iPad is still running iOS 11, your iPad is too far behind in iOS upgrades/updates.

You need to connect that iPad to a full Mac or Windows PC computer, running the latest iTunes version for Mac or PC and use the iTunes Software Update feature/option to have the iTunes application upgrade your iPad to iPadOS 13.6.1.

Best of Luck to You!

What is the “A” model number of your iPad?

The “A” model number of your iPad can be found on the lower area of the aluminium back of your iPad in small print letters right underneath the large, bold printed” iPad”.