Formal:
* आप कैसे हैं? (aap kaise hain?) - This is the most polite and formal way to ask "how are you?" and is suitable for elders, people you don't know well, or in professional settings.
Informal:
* तुम कैसे हो? (tum kaise ho?) - This is a more casual way to ask "how are you?" and is suitable for friends, family, and people you know well.
Informal and friendly:
* क्या हाल है? (kya haal hai?) - This is a very common and informal way to ask "how are you?" and is often used with close friends and family.
Other variations:
* आप ठीक हैं? (aap theek hain?) - This literally translates to "are you okay?" and is a slightly more informal way to ask "how are you?".
* आपकी तबीयत कैसी है? (aapki tabiyat kaisi hai?) - This literally translates to "how is your health?" and is a more formal way to ask "how are you?".
It's important to use the appropriate form depending on the context and your relationship with the person you're talking to.