string file_html = @"K:\hdoc.html";
string file_pdf = @"K:\new.pdf";

try
{
    DuoDimension.HtmlToPdf conv = new DuoDimension.HtmlToPdf();
    conv.Header = "Invoce Document";
    conv.Footer = "* If payment made by Bank transfer kindy please forward to us the copy of the bank transfer slip";
    conv.OpenHTML(file_html);
    conv.SavePDF(file_pdf);
    System.Diagnostics.Process.Start(file_pdf);
}
catch (Exception ex)
{
    MessageBox.Show(ex.Message);
}

Dim file_html As String = "K:\hdoc.html"
Dim file_pdf As String = "K:\new.pdf"

Try
    Dim conv As New DuoDimension.HtmlToPdf()
    conv.Header = "Invoce Document"
    conv.Footer = "* If payment made by Bank transfer kindy please forward to us the copy of the bank transfer slip"
    conv.OpenHTML(file_html)
    conv.SavePDF(file_pdf)
    System.Diagnostics.Process.Start(file_pdf)
Catch ex As Exception
    MessageBox.Show(ex.Message)
End Try