how to change extension in address bar is like a .aspx, ascx

This can be done via 2 ways-
1. If you are using IIS7.5+, you can configure this in IIS settings and this will need to be done for each page.
2. You can write below code in Global.asax page of the application in Application_BeginRequest(). The below code will redirect HTML pages to your ASPX pages.

Sub Application_BeginRequest(ByVal sender As Object, ByVal e As EventArgs)
        ' Fires at the beginning of each request
        If Request.PhysicalPath.ToLower().EndsWith(".html") Then
                Context.RewritePath(Request.PhysicalPath.Replace(".html",".aspx), False)
        End If
End Sub