Here are 10 things your welcome letter or email to new members must include plus a template that can be customized for your organization. A "thank you for joining" membership letter should include a personalized greeting to the new member.Use the member's first name in your salutation. We have an overview of how to write a tenant welcome letter, what it should include and when to send it. We've also included a free template that you can use! I am writing to extend a warm welcome to you as our newest tenant here at GreenTech Apartments. We are delighted to have you join our community. Welcome to the Blue Bird Audubon Society. As a new member of our Chapter, we hope to serve you in many ways. 1. Enter the date at the top of the letter.