If you have a few domain names with different extensions and you want all of them to open the very same website, you could have the site under one of them and forward the rest. There are different approaches to forward one Internet domain name to another, including the so-called domain parking. If your website hosting package allows it, though, it shall be better if you host all of the domains and create a URL redirect, not a domain redirect. The primary difference between the two is that while a domain is hosted, you may still have content for it, create subdomains, email addresses, and so on., while with a parked domain you can't do any of those things. As an illustration, if you're building localized sites under different country-code domains, you will be able to work on them, but in the meantime, people shall be forwarded to the primary website.