Complete setup for htaccess

Install below
sudo apt-get install apache2-utils

Modify the file below
/etc/apache2/apache2.conf

<Directory /var/www/>
    Options Indexes FollowSymLinks
    AllowOverride All
    Require all granted
</Directory>

Add the file .htaccess to any folders you wish to password protect insert the code below

AuthName "Login message here"
AuthType Basic
AuthUserFile /path/to/password/file/.htpasswd
require valid-user

create the /path/to/password/file/.htpasswd  (keep it out of the web directory)

add users with the following command

sudo htpasswd /path/to/password/file/.htpasswd new_user

Dont forget to restart Apache2 when finished.