If you have already purchased and entered a stock item that you want to use for a job or you have the item in stock, you can use the Inventory Adjustments window for recording the usage of that item. At this time, you can specify the job information for costing purposes.
Note: The cost applied to the job is determined by the item's costing method.
You don't need to do this if you'll bill your customers for the inventory item by selecting it as a line item with the job on the sales invoice. The cost will be applied at the time the invoice is saved.