test.cs

using (TXTextControl.ServerTextControl tx = new TXTextControl.ServerTextControl())
{
    tx.Create();
   
    string html = File.ReadAllText("sample.html");
 
    // load HTML string
    tx.Load(html, TXTextControl.StringStreamType.HTMLFormat);

    // change HTML root style BODY
    TXTextControl.ParagraphStyle bodyStyle = tx.ParagraphStyles.GetItem("BODY");
    bodyStyle.FontName = "Times New Roman";
    bodyStyle.Apply();

    // save as PDF
    tx.Save("output.pdf", TXTextControl.StreamType.AdobePDF);
}