Get help drafting the welcome letters to the new members of your nonprofit organization with these two useful writing templates! 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. State the purpose of the letter in the opening sentence and if you are referring to a bill, include the bill number, author and topic. 29 Unique Letter Greetings to Make a Lasting Impression. Greetings! Sample: Letter of Wishes to Trustees. Below is a sample letter of wishes that can be sent to the trustees or to the administrators of your. Trying to write a membership renewal letter but don't know where to start? Below is a sample new member welcome letter that you can use to reinforce your member's decision to join your facility. Here are 10 things your welcome letter or email to new members must include plus a template that can be customized for your organization.