How to set PDF size

How to set paper size, resolution, left, etc
reference resources wkhtmltopdf,but It still didn’t succeed

protected override string GetFormArchive()
string html=base.GetFormArchive();
string outputFilename=this.StoragePath + @"\form_archiveNew.pdf";

// System.IO.TextWriter myWriter = new System.IO.StringWriter();
// HtmlTextWriter htmlWriter = new HtmlTextWriter(myWriter);

    SelectPdf.HtmlToPdf converter = new SelectPdf.HtmlToPdf();
    converter.Options.MarginLeft = -15;
    SelectPdf.PdfDocument doc = converter.ConvertHtmlString(html);
    FileInfo f = new FileInfo(outputFilename);
    if ( !(f.Exists) ){
        doc.Save(this.StoragePath + @"\form_archiveNew.pdf");

return html;

answer:NuGet Gallery | Select.HtmlToPdf 21.1.0

API:Resizing Content During Conversion with Select.Pdf Html to Pdf Converter