Thank you all.
The unofficial guide
Creating a multisig wallet is more helpful than the official guides on Electrum website,
Multisign Wallets.
With your help, I know that I can stop the process anytime and can do it for each cosigner to get their master public key.
Two questions that I don't get from those articles
Do I need Bitcoin, satoshi to sign a transaction as one of cosigner?
If the wallet is 2-2 cosigner, do all two cosigners have to spend satoshi for transaction fee when signing it?
If both cosigners have to spend fee, a total transaction fee from a multi-sign wallet will be higher than from a single-sign wallet.
Or only one co-signer who execute the transaction will spend transaction fee?
I did not use Bitcoin multi-signature wallet but with smart contract multi-signature wallet, only the last cosigner who execute transaction must have native currency for on-chain transaction fee.
Can I use a seed from single signature wallet and gets its master key as a cosigner for a multi-sign signature wallet? or do I have to use a seed from a multi-sign wallet with its master public key?