ASK A QUESTION "I'm doing fine" in Spanish?
how are you?
Hola and welcome to the forum.
¿Cómo estás? = How are you? (informal)
Estoy bien, gracias = I'm doing well / fine, thank you.
There are dozens of way to respond to this question that would all mean (pretty much the same thing). What are you asking?
¡Maravillosa! Gracias por preocuparte por mi