I assume you are talking about Webservice in the provider side. The 'object WSDL name' is not editable unless you have a list of object as your parameter type or return type in the microflow. This value is not required for Mendix to generate WSDL when the type is not a list, thus it is disabled.
Documentation: https://world.mendix.com/display/refguide5/Operations
Also when the type is a list it's disabled. That's the problem.