Dear …
Congratulations on your appointment to the Board of Directors of __(name of organization)__. We are both honored and very pleased that you have decided to accept a position on our executive board. __(name of organization)__ is fortunate to have an individual of your caliber leading us into a successful future.
As we move forward, our organization will be facing some unique and exciting challenges. The assurance that we will overcome these challenges has been strengthened by your decision to join our board. We know your experience and education will provide us with the kind of valuable leadership qualities we need to propel our company into the future.
Welcome, __(name)__. We are thrilled that you are part of our executive board and look forward to the new milestones we will achieve through your leadership contributions.
Sincerely,