title: Write digital signature in all .pdf files
body: <p>All the time I was working with web forms, now I have task to make winForm who will read all .pdf files in one folder and implement to him a digital signature.I have that digital signature with extension .pfx.I have following code, but I don't know how to use it, because I'm really new to this.Please help me!-I appreciate your help. I need all windows form because I don't know how that funkcionate. </p>
  
  <pre><code>PdfFileSignature pdfSign = new PdfFileSignature("input.pdf", "output.pdf");
  
  System.Drawing.Rectangle rect = new System.Drawing.Rectangle(100, 100, 200, 100);
  
  pdfSign.SignatureAppearance = "butterfly.jpg";
  
  PKCS1 signature = new PKCS1("test.pfx", "password"); // PKCS#1 or
  
  //PKCS7 signature = new PKCS7("test.pfx", "password"); // PKCS#7 or
  
  //PKCS7Detached signature = new PKCS7Detached("test.pfx", "password"); // PKCS#7 detached
  
  pdfSign.Sign(1, "Signature Reason", "Contact", "Location", true, rect, signature);
  
  //save output PDF file
  
  pdfSign.Save();
  </code></pre>