It's a common way to greet someone and inquire about their well-being.
Here are some other ways to say "How have you been?" in Spanish:
* ¿Cómo estás? (formal and informal)
* ¿Qué tal? (informal)
* ¿Cómo te encuentras? (formal)
* ¿Cómo va todo? (informal, meaning "How is everything going?")
"Cómo has estado" is a slightly more formal way to ask than "cómo estás", but it's still a perfectly acceptable greeting for friends and family.