How to enable CORS globally in ASP.NET web API core

I found this site:

https://docs.microsoft.com/en-us/aspnet/core/security/cors

However I am confused in how to enable it globally, because it seems there are 2 ways to do it, whats the difference between these 2 ways? or they do 2 different things?

public IConfigurationRoot Configuration { get; }

        // This method gets called by the runtime. Use this method to add services to the container.
        public void ConfigureServices(IServiceCollection services)
        {
            //https://docs.microsoft.com/en-us/aspnet/core/security/cors
            services.AddCors(options =>
            {
                options.AddPolicy("AllowSpecificOrigin",
                    builder => builder.WithOrigins("http://example.com")
                                        .AllowAnyHeader()
                    );
            });

            services.Configure<MvcOptions>(options =>
            {
                options.Filters.Add(new CorsAuthorizationFilterFactory("AllowSpecificOrigin"));
            });

            // Add framework services.
            services.AddMvc();
        }

        // This method gets called by the runtime. Use this method to configure the HTTP request pipeline.
        public void Configure(IApplicationBuilder app, IHostingEnvironment env, ILoggerFactory loggerFactory)
        {
            loggerFactory.AddConsole(Configuration.GetSection("Logging"));
            loggerFactory.AddDebug();

            app.UseCors("AllowSpecificOrigin");

            app.UseMvc();
        }