Simply replace the unfilled areas such as "" and "[date]" with your information.
Dear [First name],
We would like to welcome you to the [name of group] committee. Thank you so much for being willing to volunteer your time. Our [community/school/church] really does need the assistance and support of everyone in order to succeed.
We are very excited about all the activities and plans coming up. We know you will be a great help in all these endeavors, and we can't wait to here your ideas!
Everyone on the committee looks forward to meeting with you at our next meeting, which will be held on [date] at [time] at [location]. See you there!