It is respectful to respond to formality with formality. A formal wedding invitation acknowledges the status level of you, your mate and children. Children are addressed as Mistress and Master, and you and your mate's professional titles such as "Doctor" are often included before your names. Formal wedding invitations also spell out words that are commonly abbreviated, such as the time, street, avenue and the day. When acknowledging a formal wedding invitation, respond in a formal manner.
Address the senders appropriately. Formal invitations are often sent by the bride's parents. For instance, enter, "Dear Mr. and Mrs. Smith." Or if the sender is a doctor or judge, for example, acknowledge their profession: Dear Doctor Robert Smith and Mrs. Evelyn Smith, or Judge Evelyn Smith and Mr. Robert Smith.
Accept the invitation, and acknowledge the date, time and place of the ceremony in one sentence. For example, "Dr. Mitchell, Michael, Katie and I accept with great pleasure the invitation of Mr. and Mrs. Smith to the wedding of Mr. John Doe and Miss Jane Smith on Saturday, the fifteenth of May at two o'clock in the afternoon at 123 Main Street."
Include a quick note about your expectations for the wedding, such as, "We are looking forward to attending your wonderful celebration."
Enter a note for any invited guest who can't attend. For example, expand the sentence, "Dr. Mitchell, Michael, Katie and I are looking forward to attending your wonderful celebration, but unfortunately, John Jr. is unable to attend because he is still away at college."
Thank the sender, and sign the letter. You can end the letter with "Thanks" or "Sincerely Yours." Then add your full name, and sign above your printed name.
Complete the additional invitation card that requires that you enter the number of guests who will attend the wedding and reception. Place the acceptance letter and invitation card in the return envelope, and send it off.