What is Windows Communication Foundation
From msdn,Windows Communication Foundation (WCF) is a framework for building service-oriented applications. Using WCF, you can send data as asynchronous messages from one service endpoint to another. A service endpoint can be part of a continuously available service hosted by IIS, or it can be a service hosted in an application.
An endpoint can be a client of a service that requests data from a service endpoint.
Here i am creating WCF service out side of the application(ie., To be host in IIS, to use service by other end)
Open File -> New -> Project (choose WCF Workflow Service Application) like shown below image
After successful creation of project, project hierarchy will shown like below
Let we write the operationcontract in the IService1.cs to consume in the other end point