Welcome to QuickBooks Community! Let me assist you in update your tax rate.
Are you referring to the state payroll tax rate? If so, please follow these steps:
Click the Gear icon and select Payroll settings.
From the Taxes section, select your state.
Change the tax rate from the Company State Tax Information page.
Tap OK to save it.
If you don't see this option, you probably subscribed to one of our full-service payroll plans. If so, you can contact our Payroll Team so they can change it on your behalf.
Click the (?) Help icon and enter Talk to a human (then type it again when prompted).
When asked by the bot, enter "Edit Tax Rate".
Select I still need a human, then proceed with Contact us or Get help from a human.
Choose either Chat or Callback.
If what you meant is a sales tax, QuickBooks Online uses the automated sales tax. This means QuickBooks will automatically do the sales tax calculations for you. However, you can create custom tax rates to manually calculate taxes on your sales transactions.