UTunnel uses username and password authentication for the web dashboard and client application sign-in process. For VPN connections, a secure certificate-based authentication is used by default.
Enabling Authenticated Sessions adds username and password authentication for VPN connections too, in addition to the certificate-based authentication. But the user will not see an authentication screen when connecting to the VPN as an encrypted cached password is used for the authentication. If multi-factor authentication is enabled together with VPN session authentication, the user will need to enter the 2FA token during each connection attempt.