test.cs

public IActionResult Index()
{
    using (var tx = new TXTextControl.ServerTextControl())
    {
        var filename = "computers.docx";

        tx.Create();
        tx.Load($"Documents/{filename}", TXTextControl.StreamType.WordprocessingML);

        var styleManager = new StyleManager(tx);
        styleManager.ApplyStyles();

        var saveSettings = new TXTextControl.SaveSettings
        {
            CssSaveMode = TXTextControl.CssSaveMode.Inline
        };

        tx.Save($"Documents/{filename}.htm", 
            TXTextControl.StreamType.HTMLFormat, 
            saveSettings);

        using (var sr = new StreamReader($"Documents/{filename}.htm"))
        {
            ViewBag.Document = sr.ReadToEnd();
        }
    }

    return View();
}