When I generate the Profit and Lost report as in this one
the cost of revenue line is always zero ?
What configuration I need to change to make the value to change ?
First, you can check if the Cost of Revenue account value is zero. You can refer to the screenshot below: -
Next, you can check whether the product buying / manufacturing has an Expense Account assigned.
If there's no Expense Account code assigned, check if the Expense Account code has been assigned to the Product Category instead.