What is a web service?
In this rapid development era, Organizations don't prefer to build everything of their own. They prefer to use the components which can process their data and return the processed data that can be used further.
Organizations started analysing and finding such business requirements and functionalities. Due to this now multiple organisations started creating service that are specific to any particular business model in the market and can process the input provided.
For example Google Map, Amazon Web Service
Web Service allows different applications from different sources to communicate with each other. Web Services are not tied to any Operating System or Programming Language. For example Web Service built in Java can be consumed by Application built on .Net.
Web service can also be used internally in an organization network as a way to allow different application to interact with each other.