Hello, @foresiteli.
You can post your non-taxable income as a personal income so QuickBooks won't calculate taxes into it.
To learn more about the difference between personal and business income, read these articles:
Also, you may check this article for your reference about tax deductions for QuickBooks Self-Employed.
Post again if there's anything you need assistance with. I'm a few clicks away to help. Have a good day!