How to convert string into pdf and save in folder

protected void btnGeneratePDF_Click(object sender, EventArgs e)
{
   try
   {
     string sess = Session["LogId"].ToString();
            sqlCon = new SqlConnection(conString);
            sqlCom = new SqlCommand("usp_Invoice_Master", sqlCon);
            sqlCom.CommandType = CommandType.StoredProcedure;
            sqlCom.Parameters.AddWithValue("@Type", "PDF");
            
            if (sqlCon.State == ConnectionState.Broken || sqlCon.State == ConnectionState.Closed)
                sqlCon.Open();
            SqlDataAdapter da = new SqlDataAdapter(sqlCom);
            sqlCon.Close();
            DataTable dt = new DataTable();
            da.Fill(dt);
            string msg = string.Empty;
            if (dt.Rows.Count > 0)
       {

                 msg += "<p style="font-family:verdana; font-size:13px; color:#161616;">Artha Travels</p>";
                    msg += "<p>Invoice</p>";
                
                    msg += "<table width="600px" cellspacing="0" cellpadding="5" border="1"> ";


                    msg += "<tr>";
                    msg += "<td>This is testing </td>";
                    msg += "<td>" + dt.Rows[0]["Invoice No"].ToString() + "</td>";
                    msg += "<td>" + dt.Rows[0]["Client Name"].ToString() + "</td>";
                    msg += "<td>" + dt.Rows[0]["Trip Id"].ToString() + "</td>";
                    msg += "<td>" + dt.Rows[0]["Trip Type"].ToString() + "</td>";
                    msg += "<td>" + dt.Rows[0]["Trip Details"].ToString() + "</td>";
                    msg += "<td>" + dt.Rows[0]["Car Details"].ToString() + "</td>";
                    msg += "<td>" + dt.Rows[0]["Total Ammount"].ToString() + "</td>";
                    msg += "<td>" + dt.Rows[0]["Balance Ammount"].ToString() + "</td>";
                    msg += "</tr>";


                    msg += "</table>";
                    msg += "<p></p>";



              
       }
var doc1 = new iTextSharp.text.Document();

            string path = Server.MapPath("~/Invoices/Pdf");

            string pdffilename = "Invoice " + dt.Rows[0]["Invoice No"] + "(" + DateTime.Now.ToString("dd-MM-yyyy") + ")" + ".pdf";

            PdfWriter.GetInstance(doc1, new FileStream(path + "/" + pdffilename, FileMode.Create));

            doc1.Open();

       iTextSharp.text.html.simpleparser.StyleSheet styles = new iTextSharp.text.html.simpleparser.StyleSheet();

       iTextSharp.text.html.simpleparser.HTMLWorker hw = new iTextSharp.text.html.simpleparser.HTMLWorker(doc1);

       hw.Parse(new StringReader(msg));

       doc1.Close();



   }
   catch (Exception ex)
   {
       MessageBox.Show(ex.Message.ToString());
   }
   finally
   {
       if (sqlCon.State == ConnectionState.Open)
       {
           sqlCon.Close();
       }
   }
}