Hello,
Thanks for using our theme.
Elementor plugin has 2 versions: free and Pro. Elementor plugin author does not offer developer license for the Pro version and does not allow to built-in Pro version of the plugin to themes. So, you can use free version – https://xstore.helpscoutdocs.com/article/36-included-plugins of the Elementor but in case you want to get the Pro version you need to buy an individual license.
Regards