In ASP.NET Core, logging providers store the logs. You can configure multiple logging providers for your application. The default ASP.NET Core configures the following logging providers: Console, Debug, EventSource, and EventLog (on Windows).

public static IHostBuilder CreateHostBuilder(string[] args) =>
   Host.CreateDefaultBuilder(args)
      .ConfigureLogging(logging =>{
         logging.ClearProviders();
         logging.AddConsole();
      })
      .ConfigureWebHostDefaults(webBuilder =>{
         webBuilder.UseStartup<Startup>();
      });

You can create logs using the ILogger interface, which is injected into your code by the ASP.NET Core dependency injection container. The following example illustrates this.

using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;
using Microsoft.AspNetCore.Mvc;
using Microsoft.AspNetCore.Mvc.RazorPages;
using Microsoft.Extensions.Logging;

namespace Razor.Pages{
   public class IndexModel : PageModel{
      private readonly ILogger<IndexModel> _logger;
      public IndexModel(ILogger<IndexModel> logger){
         _logger = logger;
      }

      public void OnGet(){
         _logger.LogInformation("Index page visited.");
      }
   }
}

In a production application, logging is critical for swiftly diagnosing, debugging, and fixing faults. Configuring logging as soon as possible, ideally when you begin designing your application, is a best practice.