We're so happy to welcome you to the family! I wanted to share an open letter to my future daughter in law.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. Here are 10 things your welcome letter or email to new members must include plus a template that can be customized for your organization. Do you want new ways to welcome members into your church? Check out these top church membership welcome letter templates and best practices. Write a personalized "Letter to Our Future Son-In-Law" to welcome him to your family. Here's points you'll want to share with your new son. A good welcome letter acts as a travel guidepointing members to key resources, highlighting benefits, and outlining simple next steps.