For using your site in multiple languages, you have to use the plugin.
Our theme is fully compatible with the WPML plugin.
If you want to translate and use your site in multilanguage then you have to purchase and use the WPML plugin, you can further check the WPML site here: https://wpml.org/
OR you can use the Polylang plugin as well it is a free one: https://wordpress.org/plugins/polylang/
Our theme supports both plugins. So, you can use the one that you like more. WPML has more options (String translator, multicurrency, etc, you can check the list of the WPML feature and Polylang features and compare) in my opinion but if Polylang suits your need then there is no problem to use that.
Regards 8Themes Team.
One standard license is valid only for 1 project. Running multiple projects on a single license is a copyright violation.