If you've submitted or posted your resume anywhere that you suspect could have led to this company reviewing it, then the best course of action here would be to reply to the email thanking the company for their interest, and asking for more information regarding the position (and the company, if you are unfamiliar with it, although some basic internet research could fill you in). Since this was unsolicited/unexpected, I wouldn't provide any personal information until you've confirmed that it is a legitimate company and is actually interested in you.
If you haven't submitted or posted your resume anywhere, and are unsure how the company would have found it, this could potentially be a phishing scam. Do not send any personal information. If it doesn't seem like something you'd be interested in, and doesn't match up with your actual resume at all, ignore it. If it seems like they may have actually seen your resume, I recommend the same course of action as above, but with a bit more caution, and possibly a question about how they found you/your resume.