Drop Shipment is done when your customer has ordered an item that you dont manufacture. In this case you purchase the same product from another company and the ship to location will the customers address. In Oracle the steps that are followed are as follows:

Enter the order with a Dropship item >> Book >> Workflow Background Process is run>>

Then Purchase release is run>> now in PO super user>> run Requisition import>> it will create the requisition>> Autocreate the requisition to a PO>> receive the PO into thedropship subinventory>> Verify the SO lines should be shipped by now>>> Run workflow and Autoinvoice.