Beaxy offers a substantial list of order types, currently more than any other exchange and with more on the way. On the market page in the upper left corner is the order panel.
If you click on the order drop down menu, which displays Limit in the screen shot above, you will be given the list of available order types.
Simply select the order type that you wish to use and the pane will change appropriately. The same method applies for Buy or Sell orders.