Macro to insert a formula to another sheet

Hello I'm new here and I'm sorry if I've posted this in the wrong place or its a question that's already been answered.
I've been asked to create a sheet to show data from one sheet on another (in the same workbook) in different cells depending on when the work is going to be completed. So I need a popup box that asks the user what cell to put the formula to view that cell in. If anyone can help me I'd be really grateful as i am completely lost.

Thanks in advance,
Drayloc

It would help if you could create and attach a sample workbook showing what you would like to see and how you think it should work.