Get every piece of text on the screen to change. Some examples:

set (gca, ‘FontSize’, 30, ‘fontWeight’, ‘bold’);
set (findall (gcf, ‘type’, ‘text’), ‘FontSize’, 30, ‘fontWeight’, ‘bold’);

or

set(gca,’FontSize’,12,’Fontname’,’Times New Roman’);
set(findall(gcf,’type’,’text’),’FontSize’,12,’Fontname’,’Times New Roman’);