Happy Birthday is a phrase that most people want to say in various languages so that they make their foreign friends feel as if their culture is important. Spanish uses the following for happy birthday: feliz cumpleaños
Hello - ¡feliz cumpleaños! - is Happy Birthday. "felicitar a alguien por su cumpleaños" is "to wish someone a happy birthday. and : Te deseo de corazón todo lo mejor para (el dia de) tu cumpleaños!