When they received a written invitation, they would RSVP on their own stationery, offering congratulations and whether or not they would be able to attend.
With the invention of the telephone, it became customary to include a response card for formal invitations, and to ask people to RSVP by telephone for casual invitations.
But what should a response card say, what is the etiquette of response cards, and are there other ways for guests to RSVP?
The most traditional way to request a response to an invitation (any invitation, really), is to state it on the wedding invitation. In the lower left hand of the invitation, place the notation “A favour of a reply is requested” (the British spelling of favour is used to be consistent with invitation wording requesting the “honour of your presence”) or R.s.v.p. Note that only the “R” is properly capitalized, as it is the beginning of the French phrase “Respondez s’il vous plait”. Sometimes a date by which replies are needed is also included. When this method is used, it is up to the guests to write a note indicating whether they will accept or decline the invitation. Believe it or not, it usually works pretty well, and it is the most elegant approach, perfect for the bride whose taste runs to the classics like roses, Vivaldi, and pearl bridal jewelry.
For those who wish to include a response card, there are two basic options. There is the small card with a self-addressed stamped envelope or there is the postcard. The primary advantage to the postcard is that it is less expensive. You save on the cost of the response envelope, pay lower postage for the R.S.V.P. cards, and may even need less postage for the entire wedding invitation packet due to omitting the extra envelope. The reason to choose the small card with an envelope is that it is more elegant, and it does not look as though you were trying to cut corners by going with the postcards (for those brides who are concerned with such things).
As an invited guest, if you do not respond by the date specified by the couple, you may even get a call from their online RSVP company asking whether you plan to attend. The website will allow you to print out directions if you need them and will give you information about what the couple wants and needs. Not only does the couple save time and money, but you can respond in less than a minute by calling the number provided.