you can try this:"Filename.txt" file will be created automatically in the bin->debug folder everytime you run this code or you can specify path of the file like: @"C:/...". you can check ëxistance of "Hello" by going to the bin -->debug folder
P.S dont forget to add Console.Readline() after this code snippet else console will not appear.
TextWriter tw = new StreamWriter("filename.txt");
String text = "Hello";
tw.WriteLine(text);
tw.Close();
TextReader tr = new StreamReader("filename.txt");
Console.WriteLine(tr.ReadLine());
tr.Close();