Formal:
* మీరు ఏమి చేస్తున్నారు? (meeru emi chestunnaru?) - This is the most formal way to ask.
* మీరు ఏం చేస్తున్నారు? (meeru em chestunnaru?) - This is a slightly less formal version.
Informal:
* ఏం చేస్తున్నావు? (em chestunnaavu?) - This is the most common and informal way to ask, used with friends and family.
* ఏం చేస్తున్నావ్? (em chestunnaav?) - This is a shortened version of the previous phrase, also used with friends and family.
More casual:
* ఎలా ఉన్నావు? (ela unnaavu?) - This literally translates to "how are you?", but it can be used to ask "what are you doing?" in a casual setting.
* ఏం జరుగుతోంది? (em jarugutundi?) - This means "what's happening?" and can be used to ask what someone is doing.
The best way to choose the appropriate phrase depends on the person you're talking to and the situation.