how do i change the name of a column in microsoft excel?

Answer 1

If you are talking about the letters A.B.C etc at the top of each column ... those cannot be changed. They are set by the program which is used when you want to have formulas. The formulas work by recognizing the cell # with the column letter.
You can add a column if you want or delete one but not change it s name.

Answer 2

Just Double click or Right Click and rename from there.
You can't usually change the "A", "B" Etc.... but you can rename the Column Names just below the Letters
One good tip:
http://www.unlv.edu/infotech/WebCT/Tips/column_attributes.htm