The alternatives Manufacturing order and Manufacturing order suggestion are displayed here if you have selected that it is possible to create manufacturing order or manufacturing order suggestion from customer order. This is determined by the setting Create manufacturing order from customer order?, under Automatic M-/P-orders from Customer Orders under the Sales tab in the Settings procedure.
In the same section in the Settings procedure you can also activate this alternative by default using the setting Create M-order/suggestion by default in Register Customer Order?. There you can also decide how to number M-orders and projects, and also determine whether or not it should be possible to edit the M-order number on customer order row. You can also select if a purchase order should be created from a customer order.