I have downloaded template and creating sample task application.
From below reference I found Web API auto generated from my task service class.
So how can I stop this behaviour or make changes in this behavior.
Comment out the lines mentioned on that page.
// Configuration.Modules.AbpWebApi().DynamicApiControllerBuilder
// .ForAll<IApplicationService>(typeof(AbpProjectNameApplicationModule).Assembly, "app")
// .Build();
// Configuration.Modules.AbpAspNetCore()
// .CreateControllersForAppServices(
// typeof(AbpProjectNameApplicationModule).GetAssembly()
// );