https://help.tallysolutions.com/docs/te9rel60/Voucher_Entry/Order_Processing/Enabling_Order_Processing.htm

Enabling Order Processing

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.