In Angular dependency, injection is used to inject the dependencies of services. A Provider works as an instructor for the dependency injection system to resolve the dependencies. When you create any service, it comes with default @Injectable decorator that contains a default property 'providedIn,' which establishes the provider for service.

BY Best Interview Question ON 29 May 2020

Example

@Injectable({
  providedIn: 'root',
})
export class DataService {
}

You can inject the services in the root or particular module as well, and you can limit the scope of service to a particular component by using component providers.

@Component({
  providers: [DataService]
})