public static void main(String[] args) throws Exception {
Document doc = new Document();
PdfWriter writer =
PdfWriter.getInstance(doc, new FileOutputStream("unsigned_signature_field.pdf"));
doc.open();
doc.add(new Paragraph("Hello world with digital signature block."));
PdfAcroForm acroForm = writer.getAcroForm();
acroForm.addSignature("sig", 73, 705, 149, 759);
doc.close();
}
