As the name suggest Override means to hide or Remove the Detail which is already Exists .Method or Function Overriding always Occur in the Inheritance, when a base Class and Derived Class both have a same name of Method. Then we will call that Method then this will Call the Method of Derived Class and Override the Body of Base Class Method.
Suppose there is a Class Whose Name is First and there is also a second Class which uses the First Class and First Class Contains a Member Function whose name is show and Second Class also Contains a Member Function whose is show, then we will Creates the Object or Second Class and call the show Method then this will Override the Body or Statements of the First Class Member Function and this will Execute the Method of Derived Class. This is the Concept of Method Overriding.