You can make changes online through MyOSU by logging in and selecting the Employee tab. Changes must be submitted by the 15th at 5:00 PM to guarantee they will be effective for the current month.  W4 Forms are available online on the IRS website (pdf format) or from your business center payroll. Complete the form, sign, and submit it to the Central Payroll office by the 15th at 5:00 PM for the changes to be effective for the current month.