Web Service applications are server implementations that do not require clients to use a specific platform or programming language. These applications define interfaces in a language-neutral document, and they allow multiple communication mechanisms. 

Web Services are designed to work using Simple Object Access Protocol (SOAP). SOAP is a standard lightweight protocol for exchanging information in a decentralized, distributed environment. SOAP uses XML to encode remote procedure calls and typically uses HTTP as a communications protocol. 

Web Service applications use a Web Service Definition Language (WSDL) document to publish information on interfaces that are available and how to call them. On the server side, your application can publish a WSDL document that describes your Web Service. On the client side, a wizard or command-line utility can import a published WSDL document, providing you with the interface definitions and connection information you need. If you already have a WSDL document that describes the Web service you want to implement, you can generate the server-side code when you import the WSDL document.