Informal:
* Ça va: This is the most common and casual way to say "I'm okay" in French. It literally translates to "It goes."
* Bien: This means "good" and is a more direct way to say "I'm okay."
* Pas mal: This means "not bad" and can be used to express that you are doing okay, but not exceptionally well.
Formal:
* Je vais bien: This is the most formal way to say "I'm okay" and literally translates to "I am going well."
* Je me porte bien: This is a more formal and literary way to say "I'm okay." It translates to "I carry myself well."
Other expressions:
* Tout va bien: This means "Everything is going well" and can be used to express that you are doing okay overall.
* Je suis bien: This means "I am well" and is a more direct way to say "I'm okay."
Examples:
* "Comment allez-vous?" - "How are you?"
* "Ça va." - "I'm okay."
* "Bien, merci." - "Good, thank you."
* "Je vais bien." - "I am well."
The best way to choose the right expression is to consider the context of the conversation and your relationship with the person you are talking to.