Formal:
* Bonjour, je vais bien. (This is the most common and polite way to say it.)
Informal:
* Salut, ça va ? (This is a more casual greeting, and the question "ça va?" means "How are you?")
* Coucou, je vais bien. (This is even more informal, and "Coucou" is a very friendly greeting.)
You can also answer with a simple "Bien, merci." (This means "Good, thank you.")
Here are some examples of how to use these phrases:
* Formal: "Bonjour, je vais bien. Et vous?" ("Hello, I am well. And you?")
* Informal: "Salut, ça va? Moi, je vais bien." ("Hi, how are you? I am well.")
* Informal: "Coucou, je vais bien. Et toi?" ("Hi, I am well. And you?")
Remember that the best way to say "Hi, I am good" in French depends on who you are talking to and how formal the situation is.