One way:

Copy the first cell. Select the remaining cells in which the formulae
are to appear (i.e., in a column). Paste.

In article ,
flaglernet wrote:

I have an excel file with 4,000 rows and 15 columns. I need to merge three
columns so I created a new column for the merged data. Entered formula
=M1&","&N1&"/"&O1 and that worked as intended for first row. How do I apply
formula to remaining 3,999 rows?