Checkout adds sales tax for ONE state: your ministry's home state, chosen in the store's Shipping settings. An order shipped to an address in that state is charged sales tax at the rate for its zip code. An order shipped anywhere else, and an order with nothing to ship, is charged no sales tax at all. Until you choose, the home state is Georgia and tax is collected. Whether your ministry must collect sales tax at all, and where, is a question for your accountant.
Open Back Office, then Commerce, then Products; open the ☰ at the top and choose Shipping.
Turn Collect Sales Tax on or off, and pick your Home State.
Changing them needs the Settings permission, like the free-shipping amount beside them.
Read the Tax figure on an order to see what was charged.
Purchases and the order details show it. An order shipped to your home state shows the tax; any other order shows none.
What is taxed: the physical items after any coupon, plus the shipping actually charged where that state taxes shipping (always in Georgia). E-books, digital books and event tickets are never taxed.
The rate is looked up for the zip code when the customer checks out. If that look-up cannot be made, a Georgia order is charged 7% instead of waiting; an order in any other state is charged no tax rather than a guess. Either way the order records that the rate was not looked up, and the problem is logged.
A store that sells another organisation's catalogue charges tax the way that organisation has chosen.