First, find out the correct formal form of address for the king: His Royal Majesty; His Majesty the King of…, etc. This is a compilation of openings and closings from medieval manuscripts to assist you in your letterwriting.Submit your message to King Charles III. Submit your prayers, messages of well wishes and congratulations to HM King Charles III on his coronation. May this letter find you in good health and high spirits. Please DO NOT return this form until three weeks before the celebration date. It is possible to receive a belated message up to six months after the event. His Majesty The King. Messages are available to Australian citizens and permanent residents celebrating a significant birthday or wedding anniversary. His Majesty The King.