Using superscript and subscript on a Mac is very easy. You can simply do it by using the following shortcuts.
Superscript on a Mac
The shortcut for using superscript numbers, letters or text on a Mac is [Ctrl]+[Shift]+[Cmd]+[+].
Subscript on a Mac
The shortcut for using subscript numbers, letters or text on a Mac is [Ctrl]+[Cmd]+[-]