Microservice decouple the application into different domains depends on logic of responsibility. Microservices communicate with each other in a network through REST with no knowledge of how other service is working internally. This composition of different service in a framework is called Microservice architecture.
As all services are independent of each other, any bug or error in one microservice doesn’t impact another. Developer teams can also be divided this way to work on specific service. This way, it doesn’t impact the whole application stack and enables streamlined agile development practices like continuous integration and delivery.