Outputing And Inputing CSV Files In C#

using System;
using System.IO;
using System.Collections.Generic;

namespace FileAccess
{
    class MainClass
    {
        public static void Main(string[] args)
        {
            string FName;
            string LName;
            string Dpt;
            string Grade;
            string NumberOfHours;
            
            string file_name = "EmployeeDetails.txt";
            string tLine = string.Empty;
            System.IO.StreamWriter objWriter;
            objWriter = new System.IO.StreamWriter(file_name);
            
            String[] ArrayDetails = new string[5];
        
            Console.Write("Enter Emp First Name: ");
            FName=Console.ReadLine();
            Console.Write("Enter Emp Last Name: ");
            LName = Console.ReadLine();
            Console.Write("Enter Emp Department: ");
            Dpt = Console.ReadLine();
            Console.Write("Enter Employee Grade: ");
            Grade = Console.ReadLine();
            Console.Write("Enter Number Of Hours Worked: ");
            NumberOfHours = Console.ReadLine();
            ArrayDetails[0] = FName;
            ArrayDetails[1] = LName;
            ArrayDetails[2] = Dpt;
            ArrayDetails[3] = Grade;
            ArrayDetails[4] = NumberOfHours;
            List<string> LDetails = new List<string>(); // Create new list of strings
            LDetails.Add(FName); // Add string 1
            LDetails.Add(LName); // 2
            LDetails.Add(Dpt); // 3
            LDetails.Add(Grade); // 4
            LDetails.Add(NumberOfHours); // 5
            string LDetailsCSV = string.Join(",", LDetails.ToArray());
            Console.WriteLine(LDetailsCSV);
            objWriter.Write(LDetailsCSV);
            objWriter.Close();
        }
    }
}