Make to order is quite a robust feature in manufacturing systems that offer the functionality to manufacture any product only after we have received sale order from a customer.

There can be many scenarios where we do not want to stock products in our inventory or we where we sell products customized according to the needs of customers and many others. So, we can not just manufacture and stock our products and then try to sell them, instead we can have the option to start the manufacturing process only after a customer has placed their order.

There can be different set of combinations to use the make to order feature in Odoo:  

Manufacture and make-to-order:

This model automatically creates a manufacturing order whenever a sale is confirmed for the product. Configuration:

In a product, go to inventory tab and configure the routes as manufacture and make to order.