1. It is super formal.
a) Mr. Right, it's a pleasure to meet you.
b) Hey you, it's a pleasure to meet you

2. It can be formal and informal.
a) Best regarts
b) Looking forward to hear from you.

3. It is informal.
a) How are you?
b) What's up?

4. It is formal.
a) It's nice to meet you
b) What's up

5. It is informal.
a) Best regards
b) What's happening?

é de marca ,por favor alguém me ajuda ​