A market order is filled immediately against the best market price. This type of order is used when the speed of order execution is more important than the price of execution.
To place a market order at CEX.IO BROKER, go to a trading terminal and click on Buy or Sell either on the Trade or Watchlist widget.
A new order window will pop up. In the drop-down list, choose Market order. Then enter your lot size and hit Send Order.
Also, you can place a market order by right-clicking on the chart and sending the order of your choice.