Method Invocation refers to the process of calling a specific function or procedure within a program. In object-oriented programming, this typically involves using an instance of a class to access its methods. When a method is invoked, the program executes the code defined within that method, often using any provided input parameters. During method invocation, the program may also return a value or result, which can be used in further calculations or operations. This process is essential for organizing code, promoting reusability, and enhancing the overall structure of software applications.