To do this task
Only the QuickBooks Administrator can do this task.
Open the items and inventory preferences.
Go to the Edit menu and click Preferences.
In the list at the left of the Preferences window, click Items & Inventory.
In the list at the left of the Preferences window, click Items & Stock.
Click the Company Preferences tab.
On the Company Preferences tab, select the Inventory and purchase orders are active checkbox.
The next step in using inventory tracking is setting up the inventory accounts you need.