Miss. Code § 23-15-659
For the purpose of this article, for all absentee ballots that are cast in person at the office of the registrar, the absentee ballot application and the required elector certificates shall be printed on the same absentee ballot envelope, with the application being printed on the front side of the envelope and the elector's certificates printed on the back side of the envelope. Such envelope shall not be smaller than eight and one-half (8-1/2) inches by eleven (11) inches. Once a voter has completed the application, he or she shall proceed to cast his or her absentee ballot and then place the ballot in the absentee ballot envelope as otherwise provided by law. After the ballot is sealed in the envelope, the elector shall complete the elector's certificate. A signature mismatch shall not be grounds for rejecting an absentee ballot that was cast in person in the registrar's office.
Miss. Code § 23-15-659