There is an incredibly easy way to create multiple Drupal sites. You don’t need to duplicate the code. You can have multiple sites, with different content, users, and themes since each site can use a different database. They will all run on a single codebase and will be able to share modules. This is one of Drupal’s greatest features called Multi-site. It was first implemented in Drupal 4, and it is here now in Drupal 8.