To do Alt + 6 on Mac in Excel, download and install Accelerator Keys, then press Option, followed by 6.
Command: Quick Access Position 6 (user-customizable)
This is how to do Alt + 6 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 + 6 activates the sixth button in your Quick Access Toolbar. You can customize this position to any command you frequently use. The Quick Access Toolbar appears at the top-left of Excel, making these shortcuts some of the fastest ways to access your most-used features.