There’s plenty of things that you can use to make Excel do the hard work for you
When you have your Excel spreadsheet open you can see the horizontal bar showing alphabets starting from A (columns), and the vertical bar showing numbers from 1 (rows). These work like map co-ordinates, A1 being the top left cell. – If you don’t have any suitable excel-documents to try this out on, type a couple of letters on each cell on rows 1-3 on columns A and B.
Left-click with the mouse on the letter A (whole column changes colour),release the mouse, then move the mouse very slightly down on top of the bottom border of that A cell. (Mouse pointer has changed into a white pointy arrow.)
Left-click with the mouse, keep the mouse button pressed down and move with the mouse to the next empty column (C in this example). All the data has moved on one go to the new column.