How do I store the data in XML?

refer XmlSerializer Class (System.Xml.Serialization)[^] class

follow the steps
Create an entity with the properties in the form as

public class MyEntity
   {
       public string Name { get; set; }
       public string Age { get; set; }
       public string Address { get; set; }
   }

the below code is for using Asp.net application, however the concept is same for mvc or window etc..

protected void btnSave_Click(object sender, EventArgs e)
        {
            // create a folder 'xmlfiles' in the root directory
            string filePath = Server.MapPath("xmlfiles") + "//" +  "myfile.xml"; //  Path for the xml

            MyEntity entity = new MyEntity();
            // initalise the properties of the entity 
            entity.Name = txtName.Text;
            entity.Age = txtAge.Text;
            entity.Address = txtAddress.Text;
            // end 

            XmlSerializer xs = new XmlSerializer(typeof(MyEntity));
            TextWriter tw = new StreamWriter(filePath);
            xs.Serialize(tw, entity);
        }

Well... There's few ways to achieve that:

1) As the predecessors wrote: XmlSerialization is the best option for you
XML Serialization and Deserialization: Part-1[^]
XML Serialization and Deserialization: Part-2[^]
A Complete Sample of Custom Class Collection Serialization and Deserialization[^]

2) using XDocument Class (System.Xml.Linq)[^]

3) using XmlDocument Class [^]

4) using DataTable[^]'s WriteXml Method (String)[^] and ReadXml Method (String) (System.Data)[^]

Try!