How can I read the appsettings.json in a .NET 6 console application?

Add these two nuget packages in your application

Microsoft.Extensions.Configuration

Microsoft.Extensions.Configuration.Json

Then you can use ConfigurationBuilder to use appsettings.json file

var configuration =  new ConfigurationBuilder()
     .AddJsonFile($"appsettings.json");
            
var config = configuration.Build();
var connectionString = config.GetConnectionString("ConnectionString");

Getting Values from AppSettings in Console Application

Adding AppSettings in .net core app