We're so happy to welcome you to the family! 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. I wanted to share an open letter to my future daughter in law. A good welcome letter acts as a travel guidepointing members to key resources, highlighting benefits, and outlining simple next steps. Here are 10 things your welcome letter or email to new members must include plus a template that can be customized for your organization. Letter to my new daughter in law. Discover Pinterest's best ideas and inspiration for Letter to my new daughter in law.