This article shares a possible use case your app could support, as well as a sample flow that could support the use case. You aren't limited to this exact flow, but it can be a helpful jumping off point as you plan your app's implementation.
A business that operates in multiple U.S. states may need to charge and collect tax at different rates for each state. Your app can calculate the correct tax to apply.
To calculate tax for different states:
Use List Tax Calculators to check which tax calculators the site has available to use for tax calculations.
Use Create Tax Region and Create Tax Group to create any necessary regions or groups. Tax is calculated based on the tax region and tax group assigned to a product.
Instruct the site owner to update tax rates using the Tax Settings in the Wix dashboard, or add your own custom logic with the Tax Calculation Integration Service Plugin.
When a cart or checkout is updated, Wix calls Calculate Tax and your tax settings will apply.