Formal:
* आज आप कहाँ हैं? (Aaj aap kahan hain?) - This is the most formal and polite way to ask.
* आप आज कहाँ हैं? (Aap aaj kahan hain?) - This is also formal but slightly less so than the previous one.
Informal:
* आज कहाँ हो? (Aaj kahan ho?) - This is the most common and informal way to ask.
* आज कहाँ रहे हो? (Aaj kahan rahe ho?) - This means "where are you staying today?" and is a slightly more polite informal option.
Note:
* The word "आज" (aaj) means "today".
* The word "कहाँ" (kahan) means "where".
* "आप" (aap) is the formal "you," while "तुम" (tum) is the informal "you."
* "हो" (ho) is the informal present tense form of the verb "to be."
The best option depends on your relationship with the person you are speaking to.