using System;

using System.Xml;

using System.Linq;

using System.Xml.Linq;

public class Program

{

    public static void Main()

    {

        var xml = @"<drinks>

      <drink>

        <drinkImage>pepsi.png</drinkImage>

        <drinkTitle>PEPSI</drinkTitle>

        <drinkDescription>(1793-1844)</drinkDescription>

      </drink>

    </drinks>";

        var dom = new XmlDocument();

        dom.LoadXml(xml);

        var existingRoot = dom.DocumentElement;

        var newElement = dom.CreateElement("drink");

        existingRoot.AppendChild(newElement);

        var drinkImageElement = dom.CreateElement("drinkImage");

        drinkImageElement.InnerText = "ck.png";

        newElement.AppendChild(drinkImageElement);

        var drinkTitleElement = dom.CreateElement("drinkTitle");

        drinkTitleElement.InnerText = "COKE";

        newElement.AppendChild(drinkTitleElement);

        var drinkDescriptionElement = dom.CreateElement("drinkDescription");

        drinkDescriptionElement.InnerText = "Nothing";

        newElement.AppendChild(drinkDescriptionElement);

        Console.WriteLine(XDocument.Parse(dom.OuterXml).ToString());

    }

}