I have a 3000 lrow xlss.

First ,I need to insert an identical row below each current row so the xlss
would have 6000 lines with the 2 identical rows grouped together.

Then on the newly created identical row, I need to make changes to the data
in a couple of cells. The changes would be the same for all rows. Is there a
formula to make identical changes to every odd or even row? Or every other
row?