Sample Site Visit Invitation Letter. Please fill out the following form in its entirety.We will review your request and follow up with you as soon as possible. Clearly state what you are inviting the recipient to do and why it is important. Writing an effective event invitation email will earn RSVP's. I hope this email finds you well. Volunteer Activity Sample Invitation. 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. Invitation and Reservation form for the 2007 Annual Meeting - mnterritorialpioneers. You are cordially invited to join the minnesota territorial pioneers, inc.