test.cs

public ActionResult Index() {

  using (TXTextControl.ServerTextControl tx = new TXTextControl.ServerTextControl()) {
    tx.Create();

    // adding static text
    TXTextControl.Selection sel = new TXTextControl.Selection();
    sel.Text = "Welcome to Text Control\r\n";
    sel.Bold = true;

    tx.Selection = sel;

    // adding merge fields
    TXTextControl.DocumentServer.Fields.MergeField mergeField = 
      new TXTextControl.DocumentServer.Fields.MergeField() {
        Text = "{{company}}",
        Name = "company",
        TextBefore = "Company name: "
      };

    tx.ApplicationFields.Add(mergeField.ApplicationField);

    // alternatively load a template
    //TXTextControl.LoadSettings ls = new TXTextControl.LoadSettings() {
    //	ApplicationFieldFormat = TXTextControl.ApplicationFieldFormat.MSWord
    //};

    //tx.Load("template.docx", TXTextControl.StreamType.WordprocessingML, ls);

    // merge fields with MailMerge engine
    using (TXTextControl.DocumentServer.MailMerge mailMerge = 
      new TXTextControl.DocumentServer.MailMerge()) {
        mailMerge.TextComponent = tx;
        mailMerge.MergeJsonData("[{\"company\": \"Text Control, LLC\" }]");
      }

    // return result as HTML
    string result = "";
    tx.Save(out result, TXTextControl.StringStreamType.HTMLFormat);

    // alternatively save as PDF
    //byte[] baPdf;
    //tx.Save(out baPdf, TXTextControl.BinaryStreamType.AdobePDF);

    ViewBag.Document = result;
  }

  return View();
}