To 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.
In the Unit of Measure section, click the drop-down arrow and then click Disabled.
Turning unit of measure off hides units of measure throughout QuickBooks. It also causes all item quantities, prices, and costs to be shown in terms of base units only. This means that if you previously used a related unit of measure for an item in a transaction, the quantity, price, and cost of that item will change to be expressed in base units when you turn unit of measure off.
What do base unit and related unit mean?