You can keep it simple and warm. The most common things to say to someone celebrating Rosh Hashanah are:

  • “Happy Rosh Hashanah!”
  • “Shanah Tovah!” (pronounced shah-NAH toe-VAH) – it means “Good year.”
  • “Shanah Tovah Umetukah” – “A good and sweet year.”
  • “Wishing you a sweet and happy New Year.”
  • “Wishing you a year of health, peace, and joy.”

If you want a slightly longer message, you could say something like:

“Shanah Tovah! Wishing you a sweet, healthy, and peaceful New Year.”

That’s polite, respectful, and completely appropriate whether you’re a close friend, coworker, or acquaintance.