There are mainly two tools to develop WCF Application. They are
Microsoft Visual Studio
CodePlex
Microsoft Visual Studio is a package which contains developing tools to develop different types of applications like web applications, mobile applications, and desktop applications.
Codeplex is an open source project hosting site of Microsoft. It contains free tools for WCF service application development. It has been used by a large number of developers across the world to create .NET projects successfully.
Microsoft Visual Studio
Description
Microsoft Visual Studio is an Integrated Development Environment(IDE) from Microsoft. It is used to develop web applications, web services, and websites. Visual studio uses Microsoft software development platforms such as Windows API(Application Programming Interfaces), windows forms, windows communication foundation, windows store, and more.
Visual studio supports while writing a code. In Visual Studio its intelligence is generated automatically as well as code refactoring. It also has some built-in tools to include a form designer while building GUI Applications.
Visual Studio 2008 is the only Microsoft IDE available for the development of WCF service applications. There is also readily made template in Visual Studio for developing WCF Service Application.
When a WCF Service template is opened it will generate "Hello World" Service even without writing any code.
CodePlex
Description
Codeplex is an open source project, hosting a website launched by Microsoft.It has been used by a large number of developers in the entire world to create .NET Project Successfully. Codeplex was launched in June 2006 by the Microsoft. Codeplex is used for developing WCF Service applications which is offered with some tools. Those are:
WSCF.blue - This is the WCF Version of the original web services contract first tool. It is a Microsoft visual studio add-on, and also "Contract-first" development toolset that facilitates the definition of WCF Service Operations and generates a code-skeleton. An important link for same as:
https://wscfblue.codeplex.com/.
WCFProxyGenerator - A Proxy in WCF is a class that enables client applications to communicate with a service by sending and receiving messages. It actually combines a number of service details like service path, service implementation technology as well as all the methods (signature only) of the Service Contract.