I haven't mailed anything certified to IRS before.  I have a 2016 tax return 😞 to mail.     Do I mail to addresses listed for Private Delivery Service?     

Have a conundrum - 2016 Federal returns for state of Indiana went to Fresno, CA                                                                                now Federal returns for state of Indiana  go to Kansas City, MO     

 Which processing center do I send to?     I believe Kansas City but don't want to get it wrong.

Thanks for helping.