I have a doubt. Is this wallet is like coinbase? i mean in coinbase if we do any transaction there is no fee. Is this wallet also has the same feature?
no, this wallet is absolutely not like Coinbase.
Coinbase is what we call a "custodial wallet", a wallet that owns your bitcoins and will (most of the time) send those bitcoins to other people when you ask them to.
Our wallet (and all other "non-custodial wallets") will make sure that at all times YOU own your bitcoins, we don't have access to your bitcoins and you have the means (a backup of private keys etc) to take your bitcoins out of the wallet even when the wallet provider (us) would want to deny you access to it.
The service that our wallet provides is merely making the process of you using your private keys to send and receive bitcoins easier.
Because the nature of how custodial wallets own your bitcoins they can send bitcoins to other people who use the same wallet provider without having to an actual bitcoin transaction, they can just do -balance and +balance in their database in that case.
non custodial wallets can't do this because the bitcoins need to be moved from your address to the other persons address, so it
always requires paying the transaction fee to the miners for the bitcoin transaction.
A good way to seeing the big difference between the 2 wallets is also that we can't help you recover your wallet if you've lost both your password and your backup document, because there's no way we can ever touch your bitcoins, only you can with either your password or the information on the backup document!