How Make Nofity icon in C#

NotifyIcon is only applicable to WinForms - since your previous questions have mostly been web related, I thought I'd better mention that...

Create a WinForms application, and add a NotifyIcon instance onto it by dragging from the ToolBox. Add an icon to the NotifyIcon instance.
Handle the Form.Load event:

private void frmNotifyArea_Load(object sender, EventArgs e)
    {
    myNotifyIcon.BalloonTipText = "Inside the PopUp";
    myNotifyIcon.BalloonTipTitle = "Popup Title";
    myNotifyIcon.ShowBalloonTip(1000);
    WindowState = FormWindowState.Minimized;
    ShowInTaskbar = false;
    }

And the Resize event:

private void frmNotifyArea_Resize(object sender, EventArgs e)
    {
    if (WindowState == FormWindowState.Minimized)
        {
        Hide();
        }
    }

And finally the NotifyIcon.MouseDoubleClick event:

private void myNotifyIcon_MouseDoubleClick(object sender, MouseEventArgs e)
    {
    WindowState = FormWindowState.Normal;
    Show();
    }