You can use
XDocument class[
^].
For example:
const string ConstStrCheck= "";
XElement xroot = new XElement("MyRoot");
XElement xele1 = new XElement("ISAPPLICABLE", ConstStrCheck + " Applicable");
XElement xele2 = new XElement("STATENAME", ConstStrCheck + " Any");
xroot.Add(xele1);
xroot.Add(xele2);
XDocument xdoc = new XDocument();
xdoc.Add(xroot);
Result:
<MyRoot>
<ISAPPLICABLE> Applicable</ISAPPLICABLE>
<STATENAME> Any</STATENAME>
</MyRoot>