The Web services is a way of integrating Web-based applications using the XML, SOAP, WSDL and UDDI open standards over an Internet protocol.
XML is actually used to tag the data, SOAP is used to transfer the data over the internet protocol, WSDL is used to describe the availability of services and UDDI is used for to get what services are available.
Web service don’t provide any interface or GUI. Web services used to share logic, data and processes through a application interface across a network. Developers used the response (comes through Web services) to offer functionality to users.
Web services are platform independent i.e it is not dependent on operating system or programming language.
Web services do not require the use of browsers or HTML. Basically, Web services use XML and HTTP
Web services are sometimes called application services.