How to export a theme I created inside my Wordpress

In the WPMudev site you guys say I can customize the theme and export it to use in many sites I want. The customization is made in a plugin installed in my site. If I want to use this same theme I personalized in another site, how wil it work?
How can I export the theme to be used in another site? It can be customized without the Upftont plugin as a normal template?