What is the difference between parked, addon, and subdomains?
Here is a brief explanation of what it is all about so that you know what you should be going for, to match your requirements.
As the name suggests, it does not have a new domain name. It is a is a second website, with its own unique content, but will always carry the name of the parent/main domain.
As an example, you have the domain domain1.com. Its document root will be /home/username/public_html (this could vary at times). Contents will be loaded from this location when domain1 is accessed in the browser.
You decide to have a wordpress installation in a sub directory blog (/home/username/public_html/blog), which you intend to access as blog.domain1.com
This is when you go for a subdomain. The same contents can be accessed as domain1.com/blog or blog.domain1.com
If you own domain1.com, you can have many subdomains (depending on the plan you are on) as blog.domain1.com, help.domain1.com, gallery.domain1.com
It is easy to set up subdomains in cPanel.
2. An addon domain is a second website, with its own unique content. This type does require you to register the new domain name before you can host it. You can set up addon domains in cpanel.
You host domain1.com and would also want to host domain2.com too. You then need to register domain2.com and add it as an addon domain under the hosting account of domain1.com.
The document root would normally be /home/username/public_html/domain2.com (in this case),
The addon domain will look completely independent to the outside world with no means for anyone to know that this is running on an account under another site.
There are 3 ways of accessing an addon domain:
3. Parked Domain
A parked domain is NOT a unique website. This is a mechanism where you would want more than one domain name to point to the same website.
You have a main domain domain1.com to which you want to point domain2.com, domain3.com and domain4.com
All you need to do is add domain2.com, domain3.com and domain4.com as parked domains of domain1.com. Anyone accessing any of these sites will be greeted with the contents of domain1.com
You can set up parked domains in cpanel.
Parked domains, again, would require you to register the domain names in order to use them.