In order for an Item to be taxed upon purchase, the following configurations must be applied:
Navigate to the Items tab and select the Item that will be taxed. The Item's record will open.
From the Item record, click the Edit action. The Edit Item modal will open.
In the Item Attributes section, check the Is Taxable checkbox.
In the Tax Class field, select the Tax Class that the item will be associated with.
Click Save. Taxes will now be applied to the selected item.