According to the federal FTC website, “Ask 1 of the 3 credit reporting companies to put a fraud alert on your credit report. They must tell the other 2 companies. An initial fraud alert can make it harder for an identity thief to open more accounts in your name. The alert lasts 90 days but you can 
renew it.”
You can ask for an initial fraud alert on your credit report if someone has misused your personal or financial information, if you’re concerned about identity theft (but haven’t yet become a victim, or if your personal information was exposed in a data breach. A fraud alert is FREE.
An initial fraud alert can make it harder for an identity thief to open more accounts in your name. When you have an alert on your report, a business must verify your identity before it issues credit, so it may try to contact you. The initial alert stays on your report for at least 90 days. You can renew it after 90 days. It allows you to order one free copy of your credit report from each of the three credit reporting companies. Be sure the credit reporting companies have your current contact information so they can get in touch with you.
- Equifax: (800)685-1111 or https://www.alerts.equifax.com/AutoFraud_Online/jsp/fraudAlert.jsp
- Experian: (888)397-3742 or https://www.experian.com/ncaconline/fraudalert
- TransUnion: (888)909-8872 or https://www.transunion.com/fraud-victim-resource/place-fraud-alert