"Happy Birthday" is the common way to say "生日快乐" in English. If you want to say it in a more formal way, you can say "Today is (name)'s birthday" or "Wishing you a very happy birthday".
"Happy Birthday" is the common way to say "生日快乐" in English. If you want to say it in a more formal way, you can say "Today is (name)'s birthday" or "Wishing you a very happy birthday".
