An alias (sometimes called a parked domain) is one, which is different from your main domain, but opens the same content. They are very useful if you wish to attract traffic to the site, as well as for better Google indexing.
For instance, if you have a domain, say yourdomain.com, but your customers are primarily from Asia, what you want to do is additionally register yourdomain.asia and use it as an alias, as this way Google will find it easier in Asian countries.
Also, if you have a hotel, for example, getting a domain like yourdomainhotel.com will put a keyword in the name, which will also help your site be found easier in search engines.
At the same time, both yourdomainhotel.com and yourodomain.asia will open the very same website.
You can have as many aliases on your account as you wish. You can add them from your cPanel >Aliases.
Note: Adding aliases is free, but each alias has to be registered separately.
Should you experience any difficulties you can always contact our 24/7 Support Team via chat, phone and mail and they will gladly help you out.