Question: how to start social security tax withholding?
Answer: You can download the form or call the IRS toll-free at 1-800-829-3676 and ask for Form W-4V, Voluntary Withholding Request. (If you are deaf or hard of hearing, call the IRS TTY number, 1-800-829-4059.) When you complete the form, you will need to select the percentage of your monthly benefit amount you want withheld.