Form - 16 pdf digital signature

AUDITOR VINOTHKUMAR (a) (870 Points)

28 May 2014  

Dear sir,

My client office at bangalore abc & co.,  employee 1000  

but payroll prepared other consultant  for mumbai he send mail to client abc & co., pdf form 16 

my client  ask me sign the pdf form-16 digitally usb token how to one time all  form  -16  sign usb token

any software available.. i used one software available option only for (.pfx ) this not use for usb token 

pls guide me very uregent