Set up your shopping cart purchases to automatically collect taxes for those states/countries that require them.
Add or Edit Tax Rates
1. Add tax rates. From under 'Commerce' choose 'Shopping Cart'. From the main shopping cart menu choose 'Add/Edit Sales Tax'
2. Choose to 'edit' or 'delete' an existing tax rate or click the 'Add a New Tax Rate' button to create a new entry.
3. Enter in the appropriate tax information. If this tax rate is required for subscriptions as well, choose 'Yes' from the 'Tax Subscriptions' field.
4. Click the 'Add Rate' button.
Set Specific Products to Charge Tax
1. From under 'Commerce' choose 'Shopping Cart'. From the main shopping cart menu choose 'Add/Edit Products'
2. Select a product from the drop down menu or choose 'New Add New Item' and click the 'Add/Edit Shopping Cart Item' button.
3. In the 'Taxable Item' field, choose 'Yes' from the drop down menu to charge tax on the item, or select 'No' to not collect any tax.