Your credit card data is very sensitive information and should not be known by others. There are various ways to get that information, one of which is by entering the email in your inbox. Don’t just click a link that comes in your email, it could be that the link leads to a phishing site. Never give out your credit card information via email, and ignore every email that asks for that data. If someone asks for your sensitive credit card information, we suggest you investigate that person by hiring a trustworthy private investigator.
In addition, at one time you might find an interesting site and want to register for the site. Be careful every time you fill out the information on a site, if the site asks for your credit card data then you should discourage from registering for the site because it is very risky. By entering your credit card data, then most likely the owner of the site can access your credit card account and use it.