Question: I want to set "Formula" to all cells in certain column **whatever the number of rows was**.

**But i don't want to set this function to first cell "Header" of this column**.

How do i make it ?.

Answer: 
If your header is in cell A1 and your formulas need to start in A2 and go to the end, **start by selecting A2, press (and release) "End" then press "Shift+Down Arrow"**. Now everything from A2 to the end is selected and you can paste your formula. If you have no data in A2-A65535, you will select the entire range. If you have data, this will only select to the end of the list of data.
I think you may have to reword this a little for people to understand exactly what you are after.
Are you trying to reference the range of all cells in a column except for the header? Most likely you can do this using an OFFSET with a COUNTA function inside, for example to get all of column A without the header you could use:

```
=OFFSET($A$1,1,0,COUNTA(A:A),1)

```

This assumes all the other cells in A have something in up to the end of the data range, no blanks in between.

What function are you trying to point at this range?