uses ComObj;
      .....

   procedure TForm1.Button1Click(Sender: TObject);
   var
     NVsign : Variant;
     retVal : Integer;
   begin
     NVsign := CreateOleObject('Neevia.PDFsign');

     NVsign.CertificateFile := 'c:\cert.pfx';
     NVsign.CertificatePassword := 'pwd';

     NVsign.TimeStamp := true;
     NVsign.TimeServerURL := 'http://tsa.neeviaPDF.com/tsa';

     NVsign.X := 0;
     NVSign.Y := 0;
     NVSign.Width := 6;
     NVSign.Height := 2;
     NVSign.Units := 1;

     NVSign.ViewType := 2;
     NVSign.Image := 'c:\stamp.jpg';

     NVSign.Reason := 'I am the creator of this document';
     NVSign.TextColor := '#0000FF';
 
     retVal := NVsign.SignPDF('c:\in.pdf', 'c:\out.pdf');
     if retVal <> 0 then
       Application.MessageBox(PChar('Error code=' + IntToStr(retVal)),'',0)
     else
       Application.MessageBox('Done','',0);
   end;