Yes you have to, OR you can use the Polylang plugin as well: 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.