application/x-www-form-urlencoded is a media type.
This type is set in the enctype attribute of a HTML form submission and is found in the body of the resulting HTTP request.
The application/x-www-form-urlencoded format is in many ways an aberrant monstrosity, the result of many years of implementation accidents and compromises leading to a set of requirements necessary for interoperability, but in no way representing good design practices.
The payload is encoded using the URL encoding.
custname=Denise+Lawrence&custtel=555-321-8642&custemail=&size=medium&topping=cheese&topping=mushroom&delivery=19%3A00&comments=