ConfigureServices method gets call runtime to register services to DI container. After registering the dependent classes, you can use those classes anywhere in the application. The ConfigureServices method includes the IServiceCollection parameter to register services to the DI container

Configure the method gets call runtime to configure the HTTP request pipeline for application. Configure use the instance of the IApplicationBuilder that is provided by In-Build IOC container. In other words, you add the middleware in this method like routing and other custom middleware as per your application requirements