To do Alt + H B R on Mac in Excel, download and install Accelerator Keys, then press Option, followed by H, B, R.
Command: Right Border
This is how to do Alt + H B R 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 B R right Border applies a border to the right side of selected cells. This is useful for creating vertical dividers between columns.