Approved Requisition does not automatically create Approved PO

Our requirement is to automatically create an Approved PO after the requisition is approved.

During testing we found that for Non-Catalog Requisition, the Purchasing Org at Requisition Line Level is blank, however, for Requisition related to item it is populated and it automatically creates an approved PO.

Anyone came across this issue and can share details would be extremely helpful. Our main question is where is the setup that automatically populate Purchasing Org at Requisition Line.

thanks