May this letter find you in good health and high spirits. 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. Get help drafting the welcome letters to the new members of your nonprofit organization with these two useful writing templates! Here are 10 things your welcome letter or email to new members must include plus a template that can be customized for your organization. Simple yet effective welcome messages. Here are 20 engaging welcome and greeting messages and real-life examples to inspire you. We compiled a list of over 100 professional good morning messages for you to use in your business communication. Add as much or as little details as you wish. Help them start their day feeling motivated and energized!