We can use "can or could" in request, when we ask someone to do something.
- Can everyone be quite for a minute, please?
- Can you keep me informed? Yes of course.
- Could you land me ten pounds until tomorrow? Sorry I haven’t got ten pounds.
- I wonder if you could explain something to me. I‘ll try.
"Could" is often, more polite than "can".
In a request we can also use "Do you mind"….? "Or would you mind" ….? With an ing-form
- Do you mind waiting a moment? No, not at all.