Hello whitney-s-gibson,
Welcome to the QuickBooks Community. It's good to know the difference among the tax codes you've mentioned above. I'll be happy to steer you on the right path by providing the information you need to move forward.
Zero-rated is a taxable sales code that has a rate of 0% in QuickBooks. Tax-exempt means there's no taxes applied and it's non-taxable. Out of scope pertains to non-taxable goods and services with a rate of 0% in QuickBooks. I recommend consulting with your accountant to learn more about the best tax code to use for your business. Otherwise, you're more than welcome to ask other questions below or reference the following article with more info about: Common sales tax codes.
Let me know if this info helps by leaving a comment below. I'll be a message away.