By the way, does Electrum wallet need to be online at the time of private key import process?
Yes, that can be done offline.
You can even keep it offline and just make another "
watch-only" wallet on an online machine by pasting the addresses instead of private key.
Then you can use it like a cold-storage setup: Create the transaction in the online Electrum, export the 'PSBT' (
Partially Signed Bitcoin Transaction) to the offline Electrum and sign it.
Then transfer the signed raw transaction to back to the online Electrum to broadcast it.
Here's how to, read the transaction part:
bitcoinelectrum.com/creating-a-cold-storage-wallet-in-electrumAlso, once the private keys are imported into Electrum, I can move the coins from Electrum wallet without any need for additional passphrase or authentication right?
Depends if you set a password to Electrum.