Hello lisa107,
As long as you enter the employee's address and other information correctly, QuickBooks Online will be able to calculate the correct tax withholding. You can see the detailed steps on how to set up the employee: Add or edit an employee in Online Payroll.
Based on the Multistate withholding matrix, Ohio and California don't have reciprocity agreement. If the employee provides a certificate of non-residence, QuickBooks don't deduct state withholding for the employee's work state.
Also, you'll have the option to deduct state withholding for the employee's residence state. you just need to make sure the Tax Information of the employee is correct.
If you choose not to withhold for the residence state, you can select Do Not Withhold as the state filing status.
You can learn more about the multistate employment through this article: About multistate employment payroll situations.
We got you if you have additional questions about this. Have a great day!