Mo. Rev. Stat. § 115.281: Absentee ballots to be printed, when.

1. Except as provided in section 115.914, not later than the sixth Tuesday prior to each election, or within fourteen days after candidates' names or questions are certified pursuant to section 115.125, the election authority shall cause to have printed and made available a sufficient quantity of absentee ballots, ballot envelopes and mailing envelopes. As soon as possible after the proper officer calls a special state or county election, the election authority shall cause to have printed and made available a sufficient quantity of absentee ballots, ballot envelopes and mailing envelopes.

2. All absentee ballots for an election shall be in the same form as the official ballots for the election.