What is SOAP and document format?

SOAP can also be bound to TCP and UDP protocols.
Protocol structure
SOAP message format:
SOAP header
<SOAP-ENV: Envelope
Attributes>
SOAP-ENV: Body
Attributes>
SOAP-ENV: Body>
</SOAP-ENV: Envelope> is currently mainly used in web services.
SOAPAction WEB encoding is common. It indicates the starting meaning of the protocol and is common in the starting sentence of the encoding.
[Edit this section] Syntax rules
Here are some important syntax rules:
SOAP messages must be encoded in XML.
SOAP messages must use the SOAP Envelope namespace
SOAP messages cannot contain DTD references
SOAP messages cannot contain XML processing instructions
[Edit this section] basic structure of the 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>