A SOAP message is an ordinary XML document containing the following elements:
It identifies the XML document as a SOAP message.A SOAP message always appears within an envelope.
Header element is optional and it contains header information.
Body element is required and it contains call and response information.
Fault element is optional. It provides information about errors that
occurred while processing the message.
All the elements above are declared in the default namespace for the SOAP envelope:
and the default namespace for SOAP encoding and data types is: