Generally, all the SOAP based web services are written by using XML language which uses standard message format that is accepted across the universe. In this format, it is easy to read, identify the errors, avoids interoperability problems etc.
Here’s the sample SOAP message format.
POST /InStock HTTP/1.1
Host: localhost
Content-Type: application/soap+xml; charset=utf-8
Content-Length: 399
SOAPAction: “
https://www.madanswer.com/soapui”