I've got steps to help you stop tax calculations on your invoices, gm9.
When creating invoices, you can simply leave the tax column unchecked. This way, QuickBooks won't automatically add sales tax to your invoices.
If you don't collect or charge sales tax at all, you also have the option to turn off sales tax in QuickBooks Online. Just note that if you have transactions with sales tax, you'll need to delete them before turning off the feature.
Here's how to turn off sales tax in the Automates Sales Tax experience:
QuickBooks makes handling tax easier. Here's an article for your future reference in recording, adjusting, and deleting sales tax payments: Manage sales tax payments in QuickBooks Online.
Please leave a reply if you have further concerns regarding your tax calculations. I'll be around to help you out.