If you have several domain names with different extensions and you want all of them to open precisely the same website, you may have the site under one of them and redirect the rest. There are several methods to redirect one domain to another, including the so-called domain parking. If your hosting package deal permits it, though, it will be better if you host all the domains and create a URL redirect, not a domain redirect. The main difference between the two is that while a domain address is hosted, you can still have content for it, set up subdomains, e mail addresses, and many others., while with a parked domain it's not possible to do any of those things. As an example, if you're building localized sites under different country-code domain names, you'll be able to work on them, but at the same time, people shall be forwarded to the primary site.