i want to find out the maximum in a column and use the cell reference in and use in another excel formula?

Answer 1

Just use MAX().
For example, maximum in a third column would be MAX(C1:C99) /replace 99 by actual number of rows/.

Use that expression in another formula - for example, maxiumum of 3rd and 4th columns:

MAX(MAX(C1:C99),MAX(D1:D99))

Answer 2

Well, I'm sure there is a function to find the maximum value. I don't understand the rest of your question.