The Fair Credit Reporting Act (FCRA) requires each of the nationwide consumer reporting companies: Equifax, Experian, and TransUnion to provide you with a free copy of your credit report, at your request, once every 12 months. The FCRA promotes the accuracy and privacy of information in the files of the nation’s consumer reporting companies. The Federal Trade Commission (FTC), the nation’s consumer protection agency, enforces the FCRA with respect to consumer reporting companies.
This web link will answer many of your questions, provide additional links to order your free anual credit report, how to correct inacuracies or missing information on your credit report.
http://www.consumer.ftc.gov/articles/0155-free-credit-reports