First of all, you should distinguish between MVC pattern and Spring MVC.
MVC pattern is a software architecture pattern in software engineering, which divides a software system into three basic parts: Model, View, and Controller.Spring MVC is an implementation of the MVC pattern.
The front end separation and MVC are not the same thing.
Your question is too general, if you want to explain the MVC pattern in detail, obviously it is more appropriate to look for the appropriate information, if you have more granular questions, please ask me or send me a private message.