Connect the iPad to a computer with Finder on Mac or iTunes on Windows/macOS Mojave or earlier
Put the iPad into Recovery Mode
When prompted, choose Restore
Wait for the restore to complete
Set up the iPad again
If Activation Lock appears, enter the Apple ID and password previously used on the iPad
If you do not know the Apple ID or password, use Apple’s account recovery process
If the iPad is still disabled after restore attempts, contact Apple Support