Withholding of federal taxes on Social Security benefits is optional.
Call Social Security - https://www.ssa.gov/manage-benefits/request-withhold-taxes
How Do I Stop Withholding?
If you want to stop withholding, complete a new Form W-4V. After completing lines 1 through 4, check the box on line 7, and sign and date the form; then give the new form to the payer
