- Click Setup in the left-hand menu.
- Select Define Sales Tax Rates in the Billing section.

- To add a new tax item, select New Tax Set.

- Enter the Tax Set Name and Description. Select Add New Tax Item and enter the appropriate information in the New Sales Tax Item window.

- To simply add a single tax rate to an existing default Sales Tax item, select the name of the Sales Tax in the Tax Item Name column.

- Type the desired Tax Rate and modify any other desired fields.
- Click Save & Exit.