To enable purchase order, sales order, and job order processing in Tally.ERP 9, you have to activate the required features in F11: Features (F2: Inventory Features).
Enable the following features in the Order Processing section:
● Enable purchase order processing
● Allow Sales Order Processing
● Enable job order processing.
Note: When Enable job order processing is set to Yes, the options Maintain multiple Godowns and Use material in and out vouchers get enabled automatically.