There are many different kinds of fraud, spam, malware, and other scams that can be brought to your computer through email. Do not reply to any emails requesting password information. Most companies will never ask you in an email to follow a link and input personal information. If you think it may be a legitimate issue, do not follow the link in the email; instead, open a browser window, navigate to the company's site, and login there to see if it says anything about needing information. Phishing websites can look identical to real websites except for tiny differences in the URL that you may or may not notice. As a general rule never use links in an email to login to a website.