Team,
I'm happy to let you know that [name] has been promoted to a [new role within the company].
[name] has worked at [company’s name] for [length of time], and was instrumental in [address some important work and/or achievement]. Besides spending long hours in the office, [name] showed his team spirit by helping others improve their work output. We are pleased to reward that level of commitment and effort.
Do join me in congratulating [name] on this exciting news.
Best regards,
[supervisor name]
[company name]