With WP Shop Cart, you can specify tax rates by states and countries for all sales. If you are charging tax based on countries or states, then in the Tax menu, select the radio button for “Global/State Specific Tax” from Tax settings and save.
Global/State Specific Tax settings also allows you to charge sales tax based on customers billing or shipping address. By default sales tax is applied based on shipping address, but you can change it according to your requirements.
From Global Tax Rates tables, simply select the country name, enter the percentage to charge sales tax, and select whether or not to add tax on shipping cost when calculating sales tax. If you forget to add a country to the tax table in that situation, no tax rate will be applied for that country.
Follow the above instructions and add the Tax rates for states exactly the same way. If you forget to add a state in that situation, no tax rate will be applied for that state. If you have a Tax rate specified for All states in the table that will override all the tax rates for individual states.
Note: Sales tax will be only applied on the products that have Apply Tax selected “Yes”. An easy way to check this is from the Product list under Add/Edit Products