When you believe the price of a security will fall from its current level, you make a short sale. You sell the security initially and then buy it back later in a short sale.

In the stock market, short selling is a strategy that involves selling a stock for less than its current value

When placing an order to short in Equity(EQ), you must select either MIS or CO, both of which are intraday order types.

Because short equity holdings cannot be kept overnight, you cannot carry forward a short equity position; if you have not exited (purchased back) the short position, it will be squared off at 3:20 PM.
Futures and options short selling:

F&O short holdings, unlike EQ short positions, can be carried overnight. You must choose MIS or NRML as the product type to short futures or options.
MIS stands for intraday, while NRML stands for overnight.
You must square off the order or convert the position to NRML to carry it overnight if you have intraday short positions in futures and options contracts, i.e. shorted using MIS or CO product types.
If you do not square off your intraday position by 3:25 p.m. for stock derivatives, 4:45 p.m. for currency derivative positions, and 25 minutes before market closure for commodity derivatives, it will be squared off by our RMS team.