Intraday Trading is a technique of taking position in the market and closing it on the same day before market closes. Positions are not carried forward to next day.
In intraday trading, traders can buy stocks and sell them on the same day either in profit or loss. Conversely, stocks can be sold earlier and bought later on when closing the position on the same day. Again, it can be either in profit or loss.
Thus, intraday trading allows traders to play the stock markets both ways. If a trader expects stock prices to move up, he can create buy position at lower prices and sell at higher prices. If prices are expected to go lower, stocks are sold at higher prices and bought later on at lower prices on the same day.
Intraday trading allows margin trading. In margin trading, traders can take trades of big amount with less capital in their account. Hence, profits or losses can be bigger as compared to the capital put on risk.