The tax class that is used for shipping, and the default tax classes for products and customers are set in the Sales configuration.
Configure tax classes
On the Admin sidebar, go to Stores > Settings > Configuration.
In the left panel, expand Sales and choose Tax.
Expand the Tax Classes section.
Choose the tax class for each of the following:
- Set Tax Class for Shipping
- Default Tax Class for Product
- Default Tax Class for Customer
When complete, click Save Config.