.htpasswd file is just a simple text file which contains user name and encrypted password. It is Apache based login which protects and secure the specific directory on website and provide more security with the help of user name and password. first need to create a text file name as .htpasswd and generate user name and password using online tools and then copy the .htpasswd file on the server and make sure Joomla website has read access to that file. Now create the .htaccess file if for administrator directory create .htaccess file under administrator directory of Joomla website and add following lines.

AuthName "Authorisation Required"
AuthUserFile /home/.htpasswd
AuthType Basic
Require valid-user
ErrorDocument 401 "Authorisation Required"

Now this will provide an additional security so any user who wants to login and access to website has to provide additional set of credentials.