A delegate is a type-safe function pointer that holds the reference of a method and invokes it for execution. To call a method using a delegate, we follow three steps:

1. Define a delegate: [] delegate void | type ([]);

        The return type of the delegate and the method it references should match.
        Parameters of the delegate and the referenced method should have matching types.
   
     Example:
    
        public delegate void AddNumberDelegate(int x, int y);
        public void Addition(int a, int b);
   
        public delegate string SayHelloDelegate(string name);
        public static string SayHello(string name);
   

2. Instantiate the delegate: AddNumberDelegate numberDelegate = new AddNumberDelegate(program.Addition); SayHelloDelegate sayHelloDelegate = new SayHelloDelegate(SayHello);

3. Now call the delegate by passing required parameter values, so that internally the method which is bound with the delegate gets executed.

   AddNumberDelegate numberDelegate = new AddNumberDelegate(program.Addition); //First way numberDelegate(20, 60);

    //Second way
    numberDelegate.Invoke(56, 78);
   

   SayHelloDelegate sayHelloDelegate = new SayHelloDelegate(SayHello);

    //First way
    string str = sayHelloDelegate("ayyappa");
    //Second way
    string str1 = sayHelloDelegate.Invoke("Reddy");
    Console.WriteLine(str);
    Console.ReadLine();