I think the word "You okay" is rather casual. What would be good alternatives that could replace "you okay" on a formal occasion?

Native speaker’s answer
Rebecca
Yes, that's correct. "You okay" is a very casual, shortened form of "are you okay?" If you want a more formal expression to use, "are you alright?" is a good alternative. But note that there isn't a particularly formal way of saying this: you would need to tailor your questions based on the context. For example, if you are asking about one's health, instead of "are you okay," you could say: Ex: How is your health? Ex: Are you doing well these days?