If you want to give someone for example a client access to manage or upload media to a certain folder, this is a great solution.
WP file manager is a great plugin there allows you to manage files on your site installation from WordPress, this can also be used to easily upload images to specific folders in WordPress, this will also change the link of the image.
As the default public root patch is set to your website main directory, after this we simply need to add the path to the folder which you want to be accessible.
This will make only the wp-content uploads folder show in WP file manager plugin. This option is also available in some of the others file manager plugins. This was quick and simple how you change root path WP File Manager plugin.