By default, anyone can register and create a new account on the website by clicking on Register new account link or accessing this URL:
http://<website>/user/register

This option can be disabled by the Administrator if it is not appropriate for other people to register on your website.
The emails sent to the user for a new account registration can be customised as part of the system configuration located at http://<website>/admin/settings/user
All new accounts registrations must have their email address confirmed before they become active. Drupal will send an email to the specified email address requesting confirmation. It is therefore critical that you have access to the email address you use when registering on the website.

Important: There can never be two accounts on the website having the same email address. Drupal will simply not allow this to happen.

Exercise:

1. Logout
2. Enter the URL http://<website>/user/register
3. Enter your new account details
4. If possible, check your email account and follow the directions in the website email
5. Login using your new account details

You can view an example Flash tutorial here.