It's a formal way to ask how someone or a group of people are doing. It's often used when speaking to a group of people you don't know well.
Here are some other ways to say "How are you?" in Spanish:
* ¿Cómo estás? (Formal, singular)
* ¿Cómo está? (Formal, singular, referring to someone you are addressing with respect)
* ¿Cómo estás tú? (Informal, singular)
* ¿Cómo están ustedes? (Formal, plural)
* ¿Cómo están? (Informal, plural, or formal plural when speaking to a group of people you don't know well)