Thanks for your answers, I am really new to odoo and as they tell me that automatically generates an order to deliver once the purchase order is confirmed, because no, the order to deliver is not being created.

for the moment as we are starting in odoo we are not using the sales module, we simplify it just by creating the purchase and making the delivery, this for an internal issue.

I would appreciate if you could help me a little more in this topic

I appreciate so much

Hello

i think you are asking about the drop shipping concept in odoo.  when confirm the sale order it will create purchase order and while you confirm generated PO it will create the Delivery Order. 

please refer below link for same.

https://www.odoo.com/documentation/user/12.0/purchase/purchases/rfq/dropshipping.html

Hello,
Delivery orders are connected to Sales order & shipments involves in purchase order. But before that while you create any product it should be stock able type & need to set other parameters as well like control purchase, routes, invoicing policies.  You need not to create any delivery order or shipment, it by default  create from odoo. In that you can create &  validate  multiple shipments first & product will automatically  gets available in sales order.

Odoo will automatically create the delivery order for you when you confirm the PO  as long as your product is either set to consumable or stockable not service. If it is not creating the delivery order then there is something wrong with your odoo install. You can run a test on runbot.odoo.com