The type of order will result in entering the market at a certain level under certain conditions. The market order simply instructs your broker to buy or sell a security at the current market price. You would use this order if you want to ensure that your order is executed.
Market orders are the most simple form of buy or sell orders.
When you place the order it will be executed at the current market price. The market order is used when you want to get into or out of a position quickly. For a buy order you will get filled at the ask price and for sell orders you will get filled at the bid price at the time your order comes up. In volatile markets when the price is changing rapidly, your order may fill at a price quite different from the price at the time you placed the order. The limit order specifies a price the trader is willing to pay for a security.