What is the use of WCF Service

Here are some points for usage of WCF Service:

Microsoft Windows Communication Foundations (WCF) provide security features for any application.
The key security features in WCF: Auditing, Authentication, Authorization, Confidentiality, and Integrity.
Transfer data from client to server and server to client with security using HTTPS, TCP, Named Pipes and MSMQ.

Transfer data or message with encrypted mode from one point to another using WCF.
It provides end-to-end security because message security directly encrypts and signs the message; having intermediaries does not break the security.
Message security is transport-independent and can be used with any transport protocol.