This command seems to work for changing the font used in output

$PrePrint = Style[#, FontFamily -> "Arial"] &;  Is there a way to make a button which can in a way or an other list all available fonts, size, color when using such a command. 1 Answer I'm uncertain if you want to know what options you can use or if you want to know how to build a button to apply the styling. If you want to list all of your system fonts, you can get them via $FontFamilies.

FontColor can be any color you like, so just choose some Hue[h,s,b] value (I find this somewhat easier to use that RGBColor[r,g,b]).

FontSize is any positive integer

FontWeight can be Bold, Plain, or DemiBold (for some fonts).

If you want flexible auto-styling just create a $styleSpec variable you can change at whim. $styleSpec={
FontFamily->"Arial",
FontColor->Hue[.6,.5,.5],
FontWeight->"DemiBold"
};
$PrePrint = Style[#, Sequence@@$styleSpec] &;


That ought to do it.

If you want to do it in a button you can do so via either a SelectedCells mechanism or via FrontEndTokenExecute, the first of which is seen here.