This information is from the Experian document, "Notification of Rights for California Consumers":

Learn the basics about SB 168, California's credit freeze [1]

How do I add an Experian security freeze?

To add an Experian security freeze, your request must be submitted in writing via certified mail.

Experian
701 Experian Parkway
P.O. Box 9554
Allen, TX 75013

In your letter Give your first name, middle initial, last name, with Jr., etc. Give your current home address and your home addresses for the past five years. Give your Social Security number, your birth date, and two proofs of residence. A proof of residence may be a copy of your driver's license, a copy of a utility bill, or a copy of a bank statement. You may pay by check, money order or credit card. If paying by credit card, give name of card, account number and expiration date.

How much will it cost?

A security freeze is free if you are a victim of identity theft and provide Experian with a valid police report or Department of Motor Vehicles investigative report.

The fee to add a security freeze is $10.

The fee to temporarily lift a security freeze is $10 to lift it for a specific period of time and $12 to lift it for a specific credit grantor. There is no fee to remove a security freeze.

Background on Security Freeze

If you are a resident of California, you have the right as of January 1, 2003 to place a security freeze on your credit report. A Security Freeze will prevent access to your credit report, allowing you to control which companies may see your credit report. However, there are certain exemptions to the Security Freeze allowed by state law that allows companies to view your report even though it is frozen.