In French, there are three common ways to ask “How are you?” that vary in formality and context. “Comment ça va ?” is the most casual and widely used expression, perfect for friends, family, or people you know well; you can simply reply with “Ça va” to say you’re fine. “Comment vas-tu ?” is slightly more polite but still informal, used when speaking to one person you’re familiar with, and the response is usually “Je vais bien, merci.” For formal situations or when addressing strangers, elders, or multiple people, use “Comment allez-vous ?”, which shows respect; the typical reply is “Je vais bien, merci. Et vous ?” Remember, “tu” forms are informal and “vous” forms are formal or plural, so choosing the right phrase helps you communicate politely and naturally in different social settings.