A congratulatory letter is a kind message written to express happiness and praise towards someone for achieving something important or significant. Full definition
The legal practitioner who spoke with newsmen in Akure, the state capital said he had written congratulatory letter to Akeredolu immediately after his Victory at the poll, pleading with him to carry everyone along. (dailypost.ng)
The awards include certificates and congratulatory letters signed by President Obama, U.S. Secretary of Education Arne Duncan, and the school principal. (ascd.org)
«Ask my big brother, Chief Nnia Nwodo, President General of Ohaneze Ndigbo, whether he replied the profound congratulatory letter President Muhammadu Buhari wrote to him immediately he was elected, before he joined (leader of the Indigenous People of Biafra) Nnamdi Kanu? (punchng.com)