What is MVC Architecture - Codeigniter Tutorial for Beginners Step by Step in Hindi
MVC extends for Model View And Controller .it is a software design pattern . codeigniter is MVC Based php framework.
Model : model use for write backend query and database logic
View : View use for display data on user screen
Controller : Controller used for write business logic of application

Work Flow Of MVC ( Model-View-Controller)
User :
User can communicate with controller
Controller :
Controller can communicate View And Model and model and view return response on controller and controller return response to user