using System;

using System.Linq;

using System.Xml;

using System.Xml.Linq;

using System.Xml.XPath;

public class Program

{

    public static void Main()

    {

        var xml = @"

                 <ShipmentHeader>

            <DocumentID>62017836-1</DocumentID>

            <DocumentReference type=""CustomerSuppliedReference"">

               <DocumentID>

                  <ID>10532</ID>

               </DocumentID>

            </DocumentReference>

            <Status>

               <Code/>

               <Description languageID=""en-us""/>

            </Status>

            <ActualShipDateTime>2023-06-07T09:16:33-04:00</ActualShipDateTime>

            <ShippingMethod>CHEAPEST METHOD W/FIRST CLASS</ShippingMethod>

            <DocumentReference type=""TrackingNumber"">

               <TrackingNumber>9200190233107605458375</TrackingNumber>

            </DocumentReference>

         </ShipmentHeader>";

        XmlDocument xmlDoc = new XmlDocument();

        xmlDoc.LoadXml(xml);

​

        XmlNodeList trackingNumberNodes = xmlDoc.SelectNodes("//DocumentReference[@type='TrackingNumber']/TrackingNumber");

        foreach (XmlNode node in trackingNumberNodes)

        {

            Console.WriteLine(node.InnerText);

        }

    }

}

​