Mo. Rev. Stat. § 51.120
Every clerk of a county commission shall keep an accurate record of the orders, rules, and proceedings of the county commission, and shall make a complete alphabetical index thereto; issue and attest all process, when required by law, and affix the seal of his office thereto; keep an accurate account of all moneys coming into his hands on account of fees, costs or otherwise, and punctually pay over the same to the persons entitled thereto; provided, that when the clerk of the circuit court of his county is a party, plaintiff or defendant, to a suit or action, the writ of summons and all other process relating thereto shall be issued by the clerk of the county commission, the reason therefor being noted on said process, and said clerk of the county commission shall, on the trial of such cause, act as temporary clerk of the circuit court and otherwise perform all the duties of the clerk of the circuit court.
§ 51.120, RSMo