Does anyone know how to increase an employee's income tax rate to 18%

Hello standupmaintenan, 

Thanks for reaching out to us here. QuickBooks is a powerful program that makes it easy for you to keep track of your payroll. I'll be happy to share more info so you're on the right track with achieving your QuickBooks goals. 

The ability to edit the an employee's tax rate is available in QuickBooks Online Accountant. If you're using this version of QuickBooks, I recommend checking out this article here that shows you how to edit the employee's taxes. Otherwise, you'll have to contact our support team outside of the Community so they can assist you further with this.  Here are our contact details: 

• Schedule a Callback or start a Chat: click (?) in the upper right in QuickBooks Online > enter "Contact support" > choose Contact Us > provide a brief summary > select Let's Talk > choose Get a callback or Start a Chat.
• Social Media: Facebook, Twitter, and Instagram.
• Support hours are from Monday to Friday between 9 a.m. and 8 p.m. ET.

I'll be one message away in case you need further assistance.