The Main method is the entry point of a C# console application or windows application. (In the term of libraries and services don’t require a Main method as an entry point.). When the application is started, the Main() method is the first method that is invoked. There can only be one entry point in a C# program. If you have more than one class that has a Main method, you must compile your program with the /main compiler option to specify which Main method to use as the entry point.

class MyClass
{
    static void Main(string[] args)
    { 
        // Display the number of command line arguments:
        System.Console.WriteLine(args.Length); 
    } 
}

Overview

1.   The Main method is the entry point of an .exe program; it is where the program control starts and ends.
2.  Main is declared inside a class or struct. Main must be static and it should not be public.
3.  Main can either have a void or int return type.
4.   The Main method can be declared with or without a string [] parameter that contains command-line arguments. When using Visual Studio to create Windows Forms applications, you can add the parameter manually or else use the Environment class to obtain the command-line arguments. Parameters are read as zero-indexed command-line arguments. Unlike C and C++, the name of the program is not treated as the first command-line argument.