Air drop is not working

You stated 4th generation iPad.

There are lots of iPads with the number 4 in them

Users that post here need to stop shortening their iPad model names

You own a brand new 2020 iPad Air 4.

The Setting for AirDrop is found in the iOS Control Center which you invoke by swiping a finger down from the top right hand corner of your iPad's screen.

You then tap and hold on any of the 4 round icon buttons in the connections block on the left.

This brings up more connection options, including AirDrop.

You might want to download/install the iPad Users Guide found here to start getting familiar with your iPad and iPadOS.

Tap the link below.

https://books.apple.com/us/book/ipad-user-guide/id1515995498

Good Luck to You!

I have an older iPad running iOS 9 and I do not see any settings or Airdrop feature on my older iPad.

Is it possible your old iPad 4th gen has no Air Drop feature, as well?

This maybe the real issue.

My iPad 2 has AirPlay but no AirDrop feature.