Hi Tina,
Thanks for reaching out to the QuickBooks community. I'll be happy to assist. QuickBooks Online is a flexible program that lets you manage your finances efficiently. When you set up the tax center within the system with one or more sales tax agencies, there is no option to removes afterwards.
As an extreme measure, and if your client just signed up for QuickBooks Online and doesn't have any data on his company file, you can purge the file completely to start completely fresh. To do so, follow the steps in this article. Keep in mind that this process will delete all data entered into the company. Once the data is deleted, it can't be restored or reversed.
Let me know if you have any other questions.
