A polite expression meaning 'congratulations,' used to formally celebrate someone's happy news (e.g. marriage, birthday, exam success). Often shortened to 'おめでとう' in casual contexts.
ご結婚おめでとうございます。末永くお幸せに。
Congratulations on your marriage. Wishing you lasting happiness.
試験に合格したそうですね。おめでとうございます。
I heard you passed the exam. Congratulations.
誕生日おめでとうございます。良い一年になりますように。
Happy birthday. I hope you have a great year.