Converting Upper case to lower case using csharp source code

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace ConsoleApplication3
{
    class Program
    {
        public static void Main()
        {

            string str;
            Console.WriteLine("Enter string in Upper case: ");
            str = Console.ReadLine();

            Console.WriteLine("String in lowercase {0}", str.ToLower());
            Console.ReadLine(); 
         
        }
    }
}

If you have any queries or suggestions, please feel free to ask in comments section.