MIS order stands for Margin Intraday Square off order used for intraday trading.
The MIS orders need to be squared off on the same day of purchase or sale. If the investor does not square off the order or convert it into other order types, the broker automatically squares off the order by the end of the trading session with some charges. Brokers also provide leverage to investors for MIS intraday trading through which they can trade in stocks beyond the available money in their trading account.
MIS trading can be done by selecting MIS as product type during buying or selling a security.