How do i add my AirPods to my Apple ID (Devices) ?

From the article below.

Your AirPods will appear in the Find My app, but they won't appear in your Apple ID device list. You can remove your AirPods from your account using Find My. 

Check your Apple ID device list to see where you're signed in - Apple Support

You can't.

"My Devices" are devices where you can sign-in with your Apple ID.