How to create event for user control - What is delegate

For me it is like a function that is having no body.

Delegate is used for callbacks of methods. It is just like a function but not having body. 

Delegate is used  to pass a method as a parameter .

 public delegate void SignatureHandler(object sender, EventArgs e);

        public event SignatureHandler SignatureEvent;

        public delegate void SignatureJSHandler(object sender, EventArgs e);

        public event SignatureJSHandler SignatureJSEvent;

        public delegate void SendConfirmationHandler(object sender, EventArgs e);

        public event SendConfirmationHandler SendConfirmationEvent;

<uc1:DigitalSignatureButton runat="server" ID="DigitalSignatureButton" OnSignatureEvent="buttonSave_OnClick" OnSignatureJSEvent="buttonSaveJS_OnClick" />