Chiming in to share additional details about sales tax, jecalderon.
As mentioned by JamesDuanT, there are factors we need to consider on how QuickBooks calculates the sales taxes. In automated sales tax, we're unable to set up a tax rate since QuickBooks will be the one to identify its rate based on those factors. Please read this article for more details: How QuickBooks Online calculates sales tax.
When recording a transaction, you can review the tax calculation. You'll see the See the math link below the Subtotal. When you click it, you can see the calculation and the tax rates. As long as the details you enter are correct, QuickBooks will calculate properly and correctly the taxes.
You can refer to the same article shared by my colleague on how to set up use automated sales tax in QuickBooks Online.
Please reply again if you need more help with this. I'm always here to help you.