How Can I Convert Output Of Windows Forms Into Pdf, Txt,

If the result is just text, you can "export" it to a simple text file with the System.IO.StreamWriter class or with System.IO.File.WriteAllText method.

To export a single-line Textbox result into a text file:

using(var writer = new System.IO.StreamWriter("output.txt"))
{
      writer.WriteLine(textbox1.Text);
}

To export a multiline Textbox or RichTextbox result into a text file:

System.IO.File.WriteAllText("output.txt", textbox2.Text);
System.IO.File.WriteAllText("output2.rtf", richTextbox1.Text);

To export to PDF format you can use some free open-source libraries:
1) iTextSharp (recommended) : http://sourceforge.net/projects/itextsharp/[^]
2)Spire.PDF : https://visualstudiogallery.msdn.microsoft.com/b590710c-efe6-4667-842e-2a592ce000cc[^]
3)PDF Clown : http://pdfclown.org/[^]

Hope this answer helps! - CCB