Very easy you don't need anything to get this done.

Hard to impossible to unfreeze with out the 10 digit PIN they mail you. Call 888-298-0045 to get a live voice - but they will not unfreeze it without the PIN!
 

Go ahead and get your mortgage account number and a couple of credit card numbers as verification.

To Unfreeze log in to https://annualcreditreport.transunion.com/fa/securityFreeze/landing you will need your PIN to unfreeze the credit.
 

Experian will ask you questions at the end to verify your entries like what county do you live in etc.

To Unfreeze your credit go here: https://www.experian.com/consumer/cac/InvalidateSession.do?code=THAW  Again you will need your PIN to unfreeze the credit.