What is formula to add a column?

To add a column in a spreadsheet application like Excel, you can use the formula =SUM(A1:A10) to sum the values in that column, for example. If you want to add a new column, simply select the column to the right of where you want the new column to be, right-click, and choose "Insert." This will shift existing columns to the right and create a blank column. Remember to adjust any formulas or references accordingly.