We can make text files in every editor, notepad is preferably used to make text files. The extension of the text file is .txt . Lets first make a simple interface that lets us enter some data in the multi-line textbox. Reading is also as simple as writing the text files.

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;
using System.IO;

namespace filestream
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        private void button1_Click(object sender, EventArgs e)
        {
            FileStream fs = File.Create("Test.txt");
            StreamWriter sw = new StreamWriter(fs);
            sw.Write(textBox1.Text);
            sw.Close();
            fs.Close();

        }

        private void button2_Click(object sender, EventArgs e)
        {
            FileStream fs = File.OpenRead("Test.txt");
            StreamReader sr = new StreamReader(fs);

            while (sr.Peek() > -1)
            {
              MessageBox.Show(sr.ReadLine());
            }
            sr.Close();
            fs.Close();

        }
    }
}