I recently received this question, “You should do a grammar post on how to respond when someone asks, ‘how are you?’ or ‘how are you doing?’ The good vs. well answer is something that gets confused a lot, myself included.”
In short, the right answer to how are you, is I am well or I am doing well. Because well answers how. Good is an adjective that has to modify a noun.
This post from Grammar Tip of the Day delves into the topic a little further. “The answer ‘I am good’ is grammatically correct –and certainly a common, useful response in everyday conversation. But the grammatical meaning is just what it says— the person is good—a good person, a religious person, maybe. In the answer ‘I am well,’ well is an adjective meaning pretty much ‘in good health’.”
Hope that helps! Thanks for asking!