To do Alt + N S H on Mac in Excel, download and install Accelerator Keys, then press Option, followed by N, S, H.
Command: Shapes
This is how to do Alt + N S H 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 + N S H shapes opens the shapes gallery where you can insert lines, rectangles, arrows, flowchart symbols, Other shapes into your worksheet.