RSVP, which stands for the French words “Repondez, s’il vous plait,” means to “please reply.” An RSVP is included on invitations to many events, particularly formal ones to request that guests confirm their attendance. Etiquette states that all recipients of an event invitation should reply within two days, three at most from the day they receive the invite. A prompt response guarantees that a host can accurately plan the event. If you want to remind people that a response is requested, however, there are a few additional tricks you can use.
Request that guests respond by a specific date in the invitation. Whether you're planning a simple party or a formal event such as a wedding, it's completely acceptable to include a date that you would like guests to respond by. The phrase “RSVP by Date” makes your point clearly and efficiently.
Include a response card for guests. An invitee should respond regardless, but a response card makes it easy for guests to note if they'll be attending and mail you a prompt answer.
Note other ways that invitees can respond promptly, such as email or a phone number. By including several methods for a potential guest to RSVP, you're clear that you expect a prompt reply.
Call the person invited if you don’t hear from them by the date requested. The RSVP is there to insist on a reply. It's not a breach of etiquette to follow up on your invitation and confirm their attendance.
Include postage on the RSVP card to make it easier for guests to respond.