Hi @estebanperalta54 ,

please check the replenishment settings

You can setup the item as Drop Ship always by doing the following setup so that the SO line will have the PO Source as drop ship by default:

@estebanperalta54  - The setting to control for this is on the Item Warehouse Details screen

Whether you setup a replenishment class to assign to items or use the override check box, you will want to set the replenishment method to Drop-Shipment for each warehouse you take sales order from (even if you only have one warehouse). 

New items, added to a Sales Order with the selected warehouse will automatically have the Mark for PO and PO Source = Drop-Ship settings flagged

Two minor notes of caution from our experience. 

1 - If you ever happen to have one of these items in stock (say from a customer return), the system will not know to un-check the mark for PO box and will continue to drop-ship an item that is in stock

2 - If you use allocating type orders and the above happens, it will route the order to both a warehouse shipment and to the create POs screen and it is difficult to know at either end that this has happened