"Ça va?" (pronounced "sah vah?")
Other options, depending on the context and level of formality:
* "Comment allez-vous?" (formal, literally "How are you?")
* "Comment vas-tu?" (informal, literally "How are you?")
* "Quoi de neuf?" (literally "What's new?")
* "Tout va bien?" (literally "Everything is going well?")
* "Comment ça va?" (pronounced "koh-mahn sah vah?", literally "How does it go?")
The best choice will depend on the situation and your relationship with the person you are speaking to.