What this fee covers
The license is issued by the county Recorder of Deeds and must be obtained before any ceremony can be performed in Missouri. The fee you pay is the county charge for issuing the license and recording the paperwork, and it is separate from any optional ceremony fees or additional certified copies you may request.
Missouri law requires a license before a marriage is valid, so the fee is tied to the issuance and recording process rather than to the ceremony itself. Because the license is a statewide legal document issued locally, the state sets the basic legal rules for who can apply and how long the license is valid, while the counties set the actual fee amount and office procedures.