WordPress introduced their multisite feature back in 2010 in WordPress 3.0. It replaced the older WordPress MU system.
Once the feature is activated on your website, multiple websites can be created from the same WordPress installation. Essentially, one set of WordPress core files powers many websites. Plugins and themes are also shared, however each website has unique directories for media uploads. The same database is also used for all websites, however separate tables are created for each website.
In this article, I would like to speak about the benefits of WordPress multisite and show you how you can activate this feature.
https://www.elegantthemes.com/blog/resources/the-complete-guide-to-creating-a-wordpress-multisite-installation