To do Alt + h i c on Mac in Excel, download and install Accelerator Keys, then press Option, followed by h, i, c.
Command: Insert Columns
This is how to do Alt + h i c on Mac in Excel with Accelerator Keys, the native ribbon and alt key shortcut solution for Mac users who get more done with Excel.
Alt + h i c inserts new columns to the left of the selected columns. The number of columns inserted equals the number selected.