whats the appropriate way of greeting others

-Good Morning, how was your day today?
-Hey, what's up?

6 answers

It depends upon whom you're greeting.

Your first sentence has a problem, though. Since you said it's morning, you wouldn't use the past tense about the day. You might say, "Good morning, how is your day going?" Or you might say, "Good evening, how was your day today?"
thnx. if i were to greet a friend, then could i say Hey, what's up?
Yes.
if i were to greet my parents, could i say that as well?
That depends upon your parents. But, in general, you'd greet older people more formally -- like -- Good evening, how was your day.

I received a robo-call today from our Congressional representative. He started the message with "Hey! This is Fred Upton." As a senior citizen, I resented this informal greeting from someone I don't know.
okay thnx