Raven plugin is developed by Artbees team specially for Jupiter X theme and Elementor.
It's required to activate it so you can use additional elements in Elementor page builder.
There are 21 custom elements added to Raven and all of them are described in this articles collection. Also, it adds the custom header and footer features to Elementor (basic edition). For more information about Raven plugin, please check this article.
Note: Please make sure the plugin server requirements are provided on your web host first. You can check the Jupiter X server requirements here. Also, read this article to understand why you should keep your active plugins at minimum.