WordPress Multisite enables users to create multiple WordPress websites with a single WordPress install. It allows for sharing of themes, plugins, and users across sites while only requiring a single upgrade. There are different types of Multisite networks including subdomain, subdirectory, and domain mapping. The process for enabling Multisite involves adding code to wp-config.php and .htaccess files. The Network Admin interface allows management of all sites. Plugins and themes must be network enabled to be used across sites. Recommended plugins include Domain Mapping and Sitewide Tags.