If the Raspberry Pi is intended for hosting one web site. The user can simply place all web page contents in the /var/www/html folder. If otherwise for hosting more than one websites, the contents of the second web site must be placed elsewhere. For example, create a subfolder for a website site_a underneath /var/www and place all its contents to the subfolder. Then, change ownership to www-data as follows:

$ cd /var/www
$ mkdir site_a
$ chown -R www-data:www-data site_a

The apache web server can redirect the second web site to its subfolder using a configuration file of a virtual host located in /etc/apache2/sites-available/. It is recommended to create a site-specific virtual host file for each and every one of all websites to be hosted.

$ cd /etc/apache2/sites-available

All virtual host files must end with .conf. In theory, one can create as many as the unit can bear. For illustration purpose, site_a.conf with minimum information required is created as follows:

<VirtualHost *:80> ServerName site_a.com ServerAlias www.site_a.com DocumentRoot /var/www/site_a ServerAdmin webmaster@localhost ErrorLog ${APACHE_LOG_DIR}/error.log CustomLog ${APACHE_LOG_DIR}/access.log combined </VirtualHost>

Likewise, create site_b.conf for another by modifying the highlighted context as shown above. To enable a virtual host,

$ a2ensite site_a.conf
$ systemctl reload apache2

To see the list of all enabled virtual hosts,

$ cd /etc/apache2/sites-enabled
$ ls -l *.conf

A virtual host if enabled will show up in this directory. In fact all are symbolic links to the conf files created in ../sites-available. To disable a virtual host, site_a for example:

$ a2dissite site_a.conf
$ systemctl reload apache2