The password protection and authentication is most important use of .htaccess files. The login procedure for these directories is automatically handled by the web browser using a pop-up login interface . you need two file for implementing password protection one is ".htaccess" file another is ".htpasswd" file.
htaccess file should contain the following.
AuthType Basic AuthName "Password Protected Directory" AuthUserFile /path/to/.htpasswd Require valid-user
To find your ".htpasswd" file path create a php file and paste following code,and upload file in same directory where you uploaded your ".htpasswd" file.
<?php $dir=dirname(__FILE__); echo "Full path to a .htpasswd file in this dir: ".$dir."/.htpasswd".; ?>
.htpasswd file should contain:
Above code will allow the user "admin" to access the password proteced directory with the password "test".