Legal Question in Business Law in California

There is no way to tell you exactly what you have to change without knowing how you do business now. However, the broad answer is you need to make them employees. You can try to do all the payroll, payroll tax accounting and payments, and mandatory paid sick leave tracking yourself with something like Quickbooks Payroll, but you would probably be much better off getting a payroll service. You will also have to get a workers compensation insurance policy. You will then have to comply with IRS reporting when you hire the contractors as employees, and any time you hire a new employee; a payroll service can help with that. Lastly, you will have to get proof of eligibility to work in the US from each employee, you and the employee must then complete a form I-9, and you must keep the I-9 forms and copies of the proof of eligibility on file for up to five years after the person stops working for you.