The message element describes how the data is going to be exchanged between the web service actors, consumer or provider.

The name attribute of the message element is used for defining a unique name among all the messages that can be defined within the WSDL 1.1 document.

The name attribute of the part element within the message element is used for defining a unique name among all the parts of an enclosing message.

The following is an example of the message element in a WSDL 1.1 file. 

<wsdl:message name = "helloWorldRequest">
    <wsdl:part name = "parameters" element = "ns:helloWorld"/>
</wsdl:message>
<wsdl:message name = "helloWorldResponse">
    <wsdl:part name = "parameters" element = "ns:helloWorldResponse"/>
</wsdl:message>