For enabling the password for the wp-admin page of wordpress. In the htaccess page of the root page add the following content.
<Files wp-login.php>
AuthName "xxxxxx Website Access"
AuthType Basic
AuthUserFile /etc/xxxx/apacheuser
Require valid-user
</Files>
<Files wp-login.php>
AuthName "xxxxxx Website Access"
AuthType Basic
AuthUserFile /etc/xxxx/apacheuser
Require valid-user
</Files>