EndPoint URL is the SOAP endpoint of STS. You must configure web service client and web service provider to these endpoints.
You can view the following details under Devices > Identity Servers > Edit > WS-Trust > EndPoint Summary:
Service Name: The name of the STS service endpoint that is configured in the web service client.
Port Name: The port that STS implements. This is configured in the web service client.
MEX EndPoint URI: The MetadataExchange endpoint of STS.
WSDL of STS Username authentication: WSDL location for username authentication. This file is used by applications that use the token service with username authentication.
WSDL of STS SAML authentication: WSDL location for SAML. This file is used by applications that use the token service with SAML authentication.