Date: __/__/____ (date)
Dear ________, (Name)
I write this letter to congratulate you as you have been selected as the employee of the month. You have always worked hard and valued this organization and you definitely deserve it.
I appreciate your passion to achieve the monthly targets and you are an inspiration for all your fellow employees. I hope that you will continue this hard work and will help this organization to grow more.
Once again, congratulations, and I wish you all the best in your future endeavours.
_________ (Contact number)