You’ve really screwed up the sales tax. I have people who are taxable setup in a sales tax that the tax doesn’t calculate. Others tax exempt that you want. To charge.

I know the importance of calculating your sales tax correctly, melvin1. Let me provide some help. 

In QuickBooks Online (QBO), taxes are calculated based on your customer's tax-exempt status, the items you sell, the location of your sales, and the destination of your shipments. If you have a customer who should be taxed but isn't calculating, please ensure to tick the checkbox in the Tax column.

On the other hand, if you have marked your customer as tax-exempt, no tax calculations will be included whenever you create a transaction.

Additionally, you can refer to this article to dig deeper into sales tax: Learn how QuickBooks Online calculates sales tax. 

Furthermore, you can customize invoices, estimates, and sales receipts in QuickBooks Online to personalize and add specific info to your sales forms.

If you have more questions regarding sales tax, please let me know in the comment section. We're always available to help you out.