Like many aspects of event production, the overall purpose and the audience of your event will determine how you approach invitation management.
If you are hosting a formal event, paper invitations sent via mail with enclosed RSVP cards remain the standard. In these cases, try to send out all invitations 8-10 weeks before the event date, with save the date cards mailed (by post or electronically) 16-18 weeks before the event. Document Solutions can help you with your invitation printing needs.
For more casual events, or events open to the public, electronic invitations or public callouts on your website may be more appropriate. Check out the resources under Communicating About Events for help with getting the word out about your event.
Regardless of the invitation format, it is important to allow attendees to submit accomodation requests. Details can be included in the RSVP or registration process, as well as on communication and marketing pieces. Suggested language might include:
<Insert host> is committed to providing universal access to all of our events. Please use this form or contact <insert email> to request accommodations (e.g., sign language interpreters, alternative formats, accessible routes) and include the event you are attending. Advance notice is necessary to arrange for some accessibility needs.