There are two types of fraud alerts: an initial alert, and an extended alert.

An initial alert stays on your credit report for at least 90 days. You may ask that an initial fraud alert be placed on your credit report if you suspect you have been, or are about to be, a victim of identity theft. An initial alert is appropriate if your wallet has been stolen or if you've been taken in by a "phishing" scam. When you place an initial fraud alert on your credit report, you're entitled to one free credit report from each of the three nationwide consumer reporting companies.

An extended alert stays on your credit report for seven years. You can have an extended alert placed on your credit report if you've been a victim of identity theft and you provide the consumer reporting company with an "identity theft report." When you place an extended alert on your credit report, you're entitled to two free credit reports within twelve months from each of the three nationwide consumer reporting companies. In addition, the consumer reporting companies will remove your name from marketing lists for pre-screened credit offers for five years unless you ask them to put your name back on the list before then.
To place either of these alerts on your credit report, or to have them removed, you will be required to provide appropriate proof of your identity: that may include your SSN, name, address and other personal information requested by the consumer reporting company.

When a business sees the alert on your credit report, they must verify your identity before issuing you credit. As part of this verification process, the business may try to contact you directly. This may cause some delays if you're trying to obtain credit. To compensate for possible delays, you may wish to include a cell phone number, where you can be reached easily, in your alert. Remember to keep all contact information in your alert current.