BTW I am using Blockchain wallet.
Again, someone right me if I'm wrong please
I am not sure if he is talking about Blockchain.com or Blockchain.info
Blockchain.com seems like Coinbase, it's not really a wallet, users can't own private keys
If Blockchain.info, it's easy to follow:
You are correct, blockchain wallet gives seed key or phrase key. OP have to write down the key as it is maintaining the order and later import in electrum wallet. Then follow my above suggestion to get private key of certain address. However, I recommend OP not to using blockchain wallet since it's an web wallet.
You're wrong, I tried to register there, not a seed key or phrase key