Used Apple Watch
I am trying to pair my handmedown Apple Watch and can’t add my AppleID and Password. It’s asking for the original Apple ID that was used to set it up.
how do I set it up with my account?
Question marked as
You can't until the previous owner has unpaired Watch with their iPhone first.
Read here what the previous owner must do => Sell, give away, or protect a lost Apple Watch - Apple Support