In China, people use to say早上好. In Taiwan, people use to say早安

Both these means "Good morning". I seldom say"早上好", I say "早" or "早呀", it's more casual. It's a little formal when we say "早上好". When I send a message on Wechat sometimes I will say "早安"。 People in Taiwan or Hong Kong like say "早安"。

“早上好”和“早安”的意思和用法完全一样。

Actually I think 早上好 can be used to greet anyone in the morning. But 早安 is a little formal, and usually used to greet old pelple.