Hello. i have just bought the new i pad air but been told its not compatible with i tunes on my mac

How old is your Mac and what MacOS/macOS is it currently running?

If you have an older Mac running an older macOS/Mac OS, you should be able to download and use iTunes version 12.8.x

I have iMacs still runnng MacOS X 10.11.6 ( EL Capitán ) and using iTunes 12.8 and have upgraded all of my family's iOS devices to iOS 14.2/iPadOS 14.2.

If you have an older Mac running a newer macOS, like macOS 10.13 High Sierra, you can still use iTunes 12.8.

If you have a newer Mac running a much newer macOS, then you need to use the macOS Finder with tbat new iPad.

To connect your iPad to a computer:

If you're using a Mac running Catalina OS or later, you'll use Finder (instead of iTunes).

If you're using a Mac running an earlier macOS, you can use iTunes.

Regards

Giulio