That mysterious “M” is simply the first letter of a traditional courtesy title: Mr., Mrs., Ms., or Miss. You’re meant to complete the title and then write your full name on the line. So “M” + “r.” becomes “Mr.,” followed by your name; “M” + “rs.” becomes “Mrs.,” and so on. It’s not asking about your meal, your marital status, or how many guests you’re bringing—just who you are.
If your preferred title doesn’t begin with M, you can still write the title you actually use, or simply write your name and skip a title altogether. And if you’re the one designing invitations, you don’t have to include the M at all. A clear “Name:” line works beautifully and avoids confusion. In the end, the only real rule is this: respond on time, with the name you want to be called, and only for the people who were truly invited.
