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. 1. Open the document in the editor.This PDF file provides a sample invitation letter template for inviting friends and family to visit you in the US. Clearly state the event's date, time, and venue. Complete the form below and submit at least 30 business days before the requested meeting or event. Begin with a Polite Greeting. Use an appropriate tone. I am writing this letter to inform you about the upcoming__( mention the occasion or the event) It has been a while since we all have met up. Make a memorable impression on potential speakers with our samples of Invitation Email to a Guest Speaker. Specify their role as a participant, presenter, speaker, or in any relevant capacity.