please do anyone know how i can add a watch only address to my wallet?
What do you mean by "watch-only addresses"? When you generate your wallet from seed you are generating an HD wallet from seeds, meaning you can generate multiple addresses/private keys from those seeds, and when you export your master public key you get the view wallet file.
You can list and track multiple master public key using third-party applications (bitcoin trackers
[1][2]) and these applications also allow you to list individual addresses.
watch only wallet is useful in tracking your coins and cannot be used to prove anything, because the proof requires signing a message, which requires a private key.
[1]
https://CoinTracker.io[2]
https://coinstats.app/