Formal:
* आप कैसे हैं? (aap kaise hain?) - This is the most common and polite way to ask.
* आप कैसे चल रहे हैं? (aap kaise chal rahe hain?) - This is a slightly more informal way of asking, but still respectful.
Informal:
* तुम कैसे हो? (tum kaise ho?) - This is used with friends and family.
* क्या हाल है? (kya haal hai?) - This is a very common way to ask, meaning "what's up?".
More casual:
* कैसे हो? (kaise ho?) - This is a shortened version of "tum kaise ho?" and is used with close friends.
It's important to choose the right phrase based on the person you're speaking to and the situation.