Can you tell me (embedded question)
This is a good way to ask for information from a bank teller, a store cashier, or a person you don't know.
You ask using an embedded question. So instead of asking, "What is my balance?" you ask:
Can you tell me what my balance is?
If you want to ask "Who is that?", you form the question this way:
Can you tell me who that is?
For more information on embedded questions, read here.