The two most common types of orders are market orders and limit orders.
Market orders A market order is an instruction to buy or sell at the best possible price.
Where there is no market in the series in the DTF, a quote request is sent to the market makers with obligations in that particular class. The market order would then be executed at the market makers' best bid or offer price for that series. A limit order is an instruction to buy or sell only at a specified price or better.