cPanel has a great feature that allows you to point multiple domains to your hosting package. There is two options to do this which are explained below.
PLEASE NOTE: Assume your main domain is domain.com and the extra domain is extra.com.
DIFFERENCES BETWEEN PARKED AND ADDON DOMAINS
A "Parked Domain" will point directly to your main website. For example www.extra.com will load the web pages from www.domain.com.
An "Addon Domain" will point to a directory within your website. For example www.extra.com will load the web pages from www.domain.com/extra.
You can set a password on an addon domain that will allow a seperate user access the site using FTP.
SIMILARITIES BETWEEN PARKED AND ADDON DOMAINS
It will appear to the website visitor that they are looking at the extra domain and not your website. For example, when the visitor goes to www.extra.com it will stay in their browsers address bar. If they click on a link that is called about.htm they will be taken to www.extra.com/abount.htm
You can add email accounts under the extra domain. For example, firstname.lastname@example.org.
You can add sub domains under the extra domain. For example, forum.extra.com.