Mo. Rev. Stat. § 473.033

The clerk, as soon as letters testamentary or of administration are issued, shall cause to be published in some newspaper a notice of the appointment of the personal representative, in which shall be included a notice to creditors of the decedent to file their claims in the court or be forever barred. The notice shall be published once a week for four consecutive weeks. The clerk shall send a copy of the notice by ordinary mail to each heir and devisee whose name and address are shown on the application for letters or other records of the court, but any heir or devisee may waive notice to such person by filing a waiver in writing. The personal representative may, but is not required to, send a copy of the notice by ordinary mail or personal service to any creditor of the decedent whose claim has not been paid, allowed or disallowed as provided in section 473.403. Proof of publication of notice under this section and proof of mailing of notice shall be filed not later than ten days after completion of the publication. The notice shall be in substantially the following form: