"Dear Parents, I am writing to thank you for two things. 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. Get help drafting the welcome letters to the new members of your nonprofit organization with these two useful writing templates! 1. Enter the date at the top of the letter. Dear Swimmer and Parents,. On behalf of The Bay Club, I would like to take this opportunity to welcome you to the Bay Club junior swim team. A good welcome letter acts as a travel guidepointing members to key resources, highlighting benefits, and outlining simple next steps. San José State University.