Having a fixed deposit is a kind of investment that is offered by banks where you can deposit a lump sum of money for a higher rate of interest than a savings account. Once the money is invested, it starts earning interest. When you make a fixed deposit you will not be able to withdraw the money before maturity, but you’ll be able to make a withdrawal after paying penalty. 

You can open a fixed deposit account with HDFC Bank through NetBanking easily. You would just have to login to NetBanking -> Accounts -> Transact -> Open Fixed Deposit. For example, if you make a deposit of Rs. 10,000 for a duration of a year at an interest of 5.6%, your maturity value will be Rs. 10,571. You would have to pay a penalty on premature closure of your fixed deposit account.