Begin with a Polite Greeting. 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.On behalf of the XYZ and the XYZ Organizing Committee, we are honored to invite you to speak at the XYZ event celebrating Cybersecurity Career Week (CCW). Write your reason for inviting them to be your "chief guest. " Tell them if they will be expected to speak to the group and if so, for how long. We have curated 15 different templates for invitation letters that can help you write invitation letters with ease. Invite people who someone in the department has a connection to. Mention them in your letter.