Column titles are used in some graphs and statistics. By default, the first column title is A, the second B and so on. If you wish to enter a new title for the column, right click on the column. The right-click menu will pop up.
Select the title option and enter your new title.
If you right-click ON the title cell (the A at the top of the column) you will not see this right-click menu, you will just jump straight to the column title box.
Even if you have given a column a title, you must still use the column’s letter in any formulas.