An angular service is an object that gets instantiated only once during the application's life cycle. These services contain methods that maintain data throughout the life of the application. An angular service is a stateless object which provides useful features, and these functions are invoked from the component of Angular. Components of Angular are controllers and directives etc. The developer can create its service with various functions.
To add any user-defined service in code, you have to implement the dependency, which will help you, the user, the service feature. Angular uses an Injectable decorator to implement the service and annotate before the class name.
To make a career in Angular, we need to know the future scope. Angular is a very popular framework, which gives several features which make it more popular. Like Angular Services, this framework has many features which make frontend coding easier. Various platforms will give you knowledge about the AngularJS framework.