We'll detail everything you need to know about how to invite a guest speaker, from the earliest planning stages to drafting a formal speaker invitation letter. Send invitations two months prior to your event.Candidates' calendars fill up quickly just prior to an election. Re: Candidate Forum. Below is a sample invitation to an event that you can send to a legislator or candidate. Below is a sample invitation to an event that you can send to a legislator or candidate. Please provide two to three weeks notice of your event in order to schedule a speaker. Invited speaker to fill out and file with the President a detailed ques-. Tionnaire prior to the issuance of any invitation. Enter your physical address in the form below in order to get a list of elected officials at the federal, state, and local levels.