“Hi. How are you?”
You hear that a lot in English, and even more often if you take a trip to America. Everyone and everywhere someone is asking YOU, from your friends and the new people you meet, to the supermarket cashier, gas station attendant, and the tellers at the bank and post office.
How ARE you? Tired, busy, stressed, hungry, sleepy. You have a cold. Your arm hurts. You’re angry at someone. You’re excited. You’re in a good mood. You’re happy. Does everyone really want to know? (And do you have to tell them?)
Mostly, “How are you?” is just a friendly greeting. You can answer however you would like. It is not necessary to think deeply or to share your trouble with anyone who asks (unless you want to.) You can smile, and answer plainly.
“Hi. I’m fine, thank you. And you?”