Open Settings on the iPad
Tap your Apple ID name at the top
Tap Find My
Tap Find My iPad
Turn on Find My iPad
Turn on Find My network
Turn on Send Last Location
Make sure Location Services is enabled
Make sure the iPad is signed in to the same Apple ID you use for Find My
Open the Find My app on your iPhone
Tap Devices
Check that the iPad appears in the list
If it does not appear, restart the iPad and check again
If needed, sign out of Apple ID on the iPad and sign back in
If needed, update iPadOS to the latest version