This is a way to ask someone to do something. It's appropriate for:
- a boss to use with the people who work for him or her
- a customer to use with a store employee
- a parent to use with his or her children
- asking a friend to help you with something
"Can you ___" is more direct than asking "Could you..."
Sometimes a person will include "maybe" in this question:
Can you maybe call him and tell him to meet us there?
Can you maybe turn the volume down just a little?