Note the difference in these two URLs for a Subdomain and which one to use on Web pages.
http://subdomain.yourdomain.com/ Correct
http://yourdomain.com/subdomain/ Not Correct
A Subdomain allows you to host another Domain name within its own directory. Although it uses your Domain name, it will appear as a totally separate Web site from your main Hosting account. This allows the Subdomain to have its own; Web pages, scripts, eMail addresses, etc. It is important to note, all Web space and other resources used by a Subdomain will count as part of the main Hosting account.
Example:
40 MB of web space used by your main Hosting account
30 MB of web space used by a Subdomain
—
70 MB total web space used
By default, the directory name will be the same as the Subdomain. Along with using its own directory you can also provide a separate FTP login. You always have access to the directory by using the login for your main account. By providing its own FTP login, this allows you to give someone access to the Subdomain directory and only that directory, keeping the rest of your Hosting account safe from tampering. You can deny access at anytime, to everyone else but yourself, by simply changing the FTP password using:
cPanel > FTP > Manage Accounts.
When you create a Subdomain using cPanel you should also remove or delete it using cPanel. This does not delete the directory created to store the files. That is a security precaution to prevent accidental removal of a directory, containing all the files related to a Subdomain, in case you have not already downloaded them. After removal using cPanel has been done, you should download the entire Subdomain directory and then delete it from your Hosting account, if no longer needed. This will free up the Web space previously used by the directory for the Subdomain.