How To Write A Congratulation Letter To An Employee . Many congratulations to both of you. Whether written formally or informally, a ‘congratulation letter’ conveys a lot of emotion, and it can make the person on the receiving end extremely happy. 49 Best Congratulation Letters (New Job, Graduation, Retirement) from templatelab.com I heard through the rumor factory that you are hoping to advance somebody and i realized i expected to think of you this letter. Accept my best wishes and blessings on behalf of my family to you and your wife. You might open with a line congratulating them on their success or receipt of an award or promotion.