To do Alt + W F F on Mac in Excel, download and install Accelerator Keys, then press Option, followed by W, F, F.
Command: Freeze Panes
This is how to do Alt + W F F 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 + W F F freeze Panes locks rows above and columns to the left of the selected cell. Frozen areas stay visible while you scroll through the rest of the worksheet.