What keyboard shortcut can be used to insert a column between existing columns?

To insert a column between existing columns in Excel, the keyboard shortcut involves using the CTRL key alongside the plus sign (+). When you select an entire column (or columns) and press CTRL and the plus key, Excel will insert a new column to the left of the selected column. This functionality allows users to easily expand their data layout without disrupting existing information.

The other keys listed, such as the SHIFT, ALT, and FN keys, do not have direct functions for inserting columns within Excel in this context. The SHIFT key is often used for selecting ranges of cells, the ALT key may access the ribbon shortcuts or other menus, and the FN key typically interacts with function keys on laptops, but does not play a role in inserting columns directly. Therefore, using the CTRL key is the appropriate method for this action.