WireGuard is a connection protocol used in the Windscribe desktop and mobile applications. It is typically faster than OpenVPN (called UDP and TCP in the apps) and more flexible than IKEv2, making it a great option for securing your online activity.
If you want to use the WireGuard protocol in the Windscribe app, go to Preferences > Connection > Connection Mode and set it to Manual. Then select WireGuard and reconnect to Windscribe in the main interface.
The main interface will let you know that you're using WireGuard: