Mo. Rev. Stat. § 143.265: Retirement income, withholding authorized, when.

Every resident receiving retirement income from an entity in this state and provided that such income is taxable by this state may have an amount withheld from such income as a payment of state income tax as required by state law. The entity administering such pension or retirement fund or program shall, upon written application from the recipient of such payments, deduct and withhold from such payments for each payment period an amount designated by the recipient, but such withholding shall not be less than ten dollars per month, and shall forward this amount to the director of revenue as prescribed by section 143.221.