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.Do you want new ways to welcome members into your church? Check out these top church membership welcome letter templates and best practices. Here are 10 things your welcome letter or email to new members must include plus a template that can be customized for your organization. 1. Enter the date at the top of the letter. Get help drafting the welcome letters to the new members of your nonprofit organization with these two useful writing templates! Below is a list of frequently requested Human services forms. Click on the form to complete and print. This is a voluntary survey.