In a rush order transaction, the customer picks up the goods or you deliver the goods on the same day as the order is placed. In the standard system, when you save this sales document type, a delivery is automatically created and billing is related to the delivery.
In the standard system, sales document type SO is saved for rush orders with immediate delivery type LF. Once the goods have been removed from storage, the goods are picked, and goods issue is posted.
Once the billing documents are created (for example, in collective processing), invoice papers are printed and sent to the customer.