Hi Elza,
Thanks for stopping by–happy to provide a little more clarification here! A WordPress multisite network is a special type of WordPress installation, which consists of a single WordPress install that houses a larger network of sub-sites. You might use a multisite network to create a social site, for example, where the main site houses content provided by the site administrator, and individual users can create their own smaller blog sites within that network. You can read more about WordPress multisite networks on WordPress’s documentation here.
For most users who wish to install our plugins on multiple sites, you’ll want to stick with our standard license types (Personal, Business, Agency, and Unlimited). A Multisite license cannot be used on multiple sites outside of a single multisite network.
I hope that helps! Thanks again, and let me know if you should have any other questions!