Once you have been introduced to someone, the next time you see that person it is important to greet him/her. In English (as in all languages), there are different ways to greet people in formal and informal situations.
Formal Greetings: Arriving
Good morning / afternoon / evening.
Hello (name), how are you?
Informal Greetings: Arriving
Hi / Hello
How are you?
What's up? (very informal)
How are you doing? (very informal)
It's important to note that the question "How are you?" or "What's up?" doesn't necessary need a response. If you do respond, these phrases are generally expected:
Very well, thank you. And you? (formal)
Fine / Great (informal)
Formal Greetings: Departing
It was a pleasure seeing you.
Goodbye.
Note: After 8 p.m. - Good night.
Informal Greetings: Departing
Bye bye / Bye
See you later/ See you
