Formal:
* Ano po ang ginagawa ninyo? (This is the most polite and formal way to ask.)
Informal:
* Ano ang ginagawa mo? (This is the most common way to ask.)
* Anong ginagawa mo? (This is a more casual way to ask.)
* Ano'ng ginagawa mo? (This is the most casual and informal way to ask.)
Other options:
* Kumusta ka? (This literally means "How are you?" but it can also be used to ask "What are you doing?" in a casual setting.)
* Ano'ng nangyayari? (This means "What's happening?" and is a good way to ask "What are you doing?" if you're curious about what someone is up to.)
The best way to choose the right phrase depends on the situation and your relationship with the person you're speaking to.