If you require some information you can say:
Could you tell me if/when/how much/why;;?
I wonder if you could tell me;;?
I'd like to know;;
I'd like some information about;;
If someone asks you for information you can reply:
As far as i know,;;
Well,in confidence,) I can tell you that I'm afraid I don't know.
I've no idea,I'm afraid I don't have that information available just now,can I call you back?
I'm not sure,I'll have to find out,Can I let you know tomorrow?
I'm afraid I can't tell you that,it's confidentail.