Monolithic architectures are the simplest form of architecture as it is having only one application layer that bundles together all the software components, and is hosted and delivered together. This type has been widely used by many small and mid-sized companies.

The main challenge in this system is during scaling up as we need to duplicate the whole system including all the features of other machines which increases the cost. Also, the failure of one feature will affect the whole system making it unreliable.

Microservices architectures are an architectural style that structures an application as a collection of small self-contained processes, modelled around a business capability. They don’t share the data structure and will be communicating through APIs.

Real life example

Monolithic architecture is like a tank in the army. It has a lot of firepower and it's crewed by a team who work together to pilot the tank. If you need more firepower you bring in another tank with another crew (which is like having multiple servers running the same CMS framework with a load balancer).
Microservices are like a team of specialists who are trained to work together or independently. You might have an officer, a gunner, a sniper, a medic, etc. You can have multiple of any of them if you need on any team and teams can be any size. This is akin to having each microservice on its own server and being able to spin up servers for any microservice as needed.

Advantges of Microservices over Monolithic

As we know that Monolithic architecture having entire application is one layer, so if application got any scalling then entire system will be collapsed. Unlike Monolithic, in Microservices we break all dependencies into smaller services to make it loosely coupled. So it case of any fault in one services it will not affect others (Fault isolation)