If you’re the only user on your system or are the primary user, you can enable the automatic login feature so that you no longer need to type your user name and password each time you start the system.
NOTE
If you choose not to set up automatic login, you still can change some aspects of the login process, such as whether all the users are listed. To do so, start System Preferences, double-click on the Accounts icon, and click on the Login Options tab.