The Share Widget is a small icon on top of your video that allows viewers to easily and quickly share your video on social media.
This option is found in your Theme. Navigate to your Theme >> Player Settings >> Share Widget to activate it:
After the activation, a widget will appear on your video at the upper right corner:
And then once clicked by a view, the various social networks to share it on will appear. The social networks used are Facebook, LinkedIn, Twitter and Pinterest.
The URL that is shared is the URL the video is embedded.