Unlicensed Users can access any SharePoint Sites based on whatever permission they have. If you add the unlicensed user to site owner group, the unlicensed user can create a site.

Does SharePoint Online require a license?

SharePoint Online is available via Office 365. Normally every user in your business that needs access to Office 365 requires a license. However, what you may not be aware of is that 'external' users do not require a license to access SharePoint Online.

Can non Microsoft users use SharePoint?

Authenticated users without Microsoft accounts

It is possible to share content with anyone who has an email address even though if it is not a Microsoft Account. In this case, a one-time access code for authentication is sent to them each time they access the file or folder.