This widget comes free with WPmozo Addons Lite. To use it, simply install and activate the free version of plugin.

https://wordpress.org/plugins/wpmozo-addons-lite-for-elementor

How to add widget on page

Once WPMozo Addons is activated it adds a number of widgets to the Elementor builder. To insert the widget, use the following steps.

1. Create/edit a page/post that uses Elementor builder.
2. Create/edit container.
3. Search widget Star Rating under WPMozo.