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?