Move the cursor to the formula where you need to enter superscripts and subscripts, click "Subscript and Superscript Template" , expand the template and select "Superscript"
 , expand the template and select "Superscript" , "Subscript"
 , "Subscript" or "Superscript and Subscript"
 or "Superscript and Subscript" .
 .
Or use shortcut keys to enter: superscript (SHIFT+^) and subscript (SHIFT+_).