We say "good Morning" in the morning in english. But it doesn't say "좋은 아침입니다." in korean. because "좋은 아침입니다" is not korean style. So that expression is wrong. "안녕하세요." is right in culture of korea.

good morning is 좋은 아침 but, implicative meaning is 잘 잤니? 안녕히 주무셨어요?

good = 좋은 morning = 아침 Who is bigger than you : 좋은 아침입니다 Who is equally age or smaller than you : 좋은 아침

Good morning means "안녕하세요?" or "좋은 아침이네요"