For our clients using Clover Register, there are two places you can add a Tax Rate. One is the "default" tax rate that you set in Clover Register. This is a single tax that is defined for a merchant or, more specifically, merchant location. For each product added to the inventory, you can set the default tax rate. Clover Register only supports one default tax rate.
With that being said, you may need to setup additional tax rates in Clover Online, based on the shipping destination. You'll want to add a tax rate for each location you are shipping to. If you need help adding tax rates in Clover Online, please visit this article. If you'd like to learn more about tax rates and compliance, please visit these resources.