From http://www.w3schools.com (Copyright Refsnes Data)

SOAP Syntax

SOAP Building Blocks

A SOAP message is an ordinary XML document containing the following elements:

An Envelope element that identifies the XML document as a SOAP message
A Header element that contains header information
A Body element that contains call and response information
A Fault element containing errors and status information

All the elements above are declared in the default namespace for the SOAP envelope:

http://www.w3.org/2001/12/soap-envelope

and the default namespace for SOAP encoding and data types is:

http://www.w3.org/2001/12/soap-encoding

Syntax Rules

Here are some important syntax rules:

A SOAP message MUST be encoded using XML
A SOAP message MUST use the SOAP Envelope namespace
A SOAP message MUST use the SOAP Encoding namespace
A SOAP message must NOT contain a DTD reference
A SOAP message must NOT contain XML Processing Instructions

Skeleton SOAP Message

<?xml version="1.0"?>
<soap:Envelope
xmlns:soap="http://www.w3.org/2001/12/soap-envelope"
soap:encodingStyle="http://www.w3.org/2001/12/soap-encoding">

<soap:Header>
  ...
  ...
</soap:Header>

<soap:Body>
  ...
  ...
  <soap:Fault>
    ...
    ...
  </soap:Fault>
</soap:Body>

</soap:Envelope>