Payroll Deductions Payroll taxation is highly regulated and in our University environment includes a number of different forms for a variety of employee scenarios. The links below will provide helpful information to guide you with answers to most of your questions. Reading and Understanding Deductions on Your Pay Stub Mandatory Tax Withholding Required for Most Employees (Federal and State) When and How to File Income Tax Returns Filling Out the Form W-4 Tax Treaties and Non-Resident Alien Guidelines