Change font sizes within the Fonts window on Mac
Change the font sizes available in the Fonts window.
In an app on your Mac, choose Format > Show Fonts or Format > Font > Show Fonts.
In the Fonts window, click the Action pop-up menu , choose Edit Sizes, then do any of the following:
Add a font size: Type a new size, then click the Add button .
Change the values on the slider: Type new values in the Max. and Min. fields.
Remove a font size: Select it in the list, then click the Remove button .
Restore the original values: Click Reset Sizes.
Click Done.