Good morning Dh,
David is correct, you are entitled to one free credit report annually from each of the three credit bureaus. The purpose is to provide consumers the opportunity to correct errors in their credit reports.
Be careful of two things:
1. David provided the correct website: https://www.annualcreditreport.com
Be careful not to be directed by search engines or your browser to imitation websites that will attempt to collect a fee from you.
2. As David correctly points out: avoid the credit scores once you are on the site. These scores are available for a fee and are NOT the same as FICO scores used by financial professionals. I have seen these scores vary by as much as 100 points.
If you are inquiring about your credit to determine if you are qualified for a mortgage, then I'd recommend contacting a Local Mortgage Banker to get prequalified. While there is an impact on your credit score from the Mortgage Banker's inquiry, according to MYFICO.com the effect is minimal (assuming you have decent credit history).