how the folder public_ html is structured

Hello, I’m trying to understand how the folder public_ html is structured for multi-site with sub-domains.
The folder public_ html contains the folder getwp.net, which is my primary domain. Inside that folder, the structure is almost the same like in a root folder. It includes a number of files and folders such as wp- themes, wp- plugins, wp-includes, cache, htaccess and config.php and so on.
Is it really necessary to have all this files under getwp.net folder?
Thank you.