* ¿Qué onda?
* ¿Cómo estás?
* ¿Qué hay?
* ¿Cómo te va?
* ¿Qué haces?
The first option, "¿Qué onda?", is a very informal way of saying "what's up" and is commonly used among friends. The second option, "¿Cómo estás?", is a more formal way of saying "how are you?" and is used in both casual and formal settings. The third option, "¿Qué hay?", is a very informal way of saying "what's up" and is often used in a playful or joking manner. The fourth option, "¿Cómo te va?", is a more formal way of saying "how are you?" and is used in both casual and formal settings. The fifth option, "¿Qué haces?", is a very informal way of saying "what are you doing?" and is often used in a casual setting.
The best way to choose which phrase to use will depend on the level of formality you want to maintain and the context in which you are speaking.