End force the application to stop running.
- closes files opened Open statement
 - clears all the application variables
 
Example:
End application on button click
Public Class Form1
Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
    End Sub
    Private Sub btn_Click(sender As Object, e As EventArgs) Handles btn.Click
        If MsgBox("Do you want to exit?", MsgBoxStyle.YesNo) = MsgBoxResult.Yes ThenEnd
End If
End Sub
End Class