public void SignDocument()
{
CertificateHolder ch = CertificateHolder.Create(MyDir + "certificate.pfx", "123456");
//By String
Document doc = new Document(MyDir + "TestRepeatingSection.docx");
string outputDocFileName = MyDir + @"\Artifacts\TestRepeatingSection.Signed.doc";
DigitalSignatureUtil.Sign(doc.OriginalFileName, outputDocFileName, ch, "My comment", DateTime.Now);
}