To do Alt + H F S on Mac in Excel, download and install Accelerator Keys, then press Option, followed by H, F, S.
Command: Font Size
This is how to do Alt + H F S 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 F S font Size lets you set the exact size of text in selected cells. You can type a specific size or choose from the dropdown list.