Multisite on single wordpress

You absolutely can have a single WordPress Multisite installation serve up more than one domain.

1. Set up Multisite. For this site, it won’t matter if you use subdirectory or subdomain. (If you plan to add other sites to this Multisite network, choose the option you’d prefer to use for those other sites.)
2. Create your new site.
3. Go to the new site’s Dashboard, and mouse over its name in the admin bar at the top of the page. Select Edit Site from the dropdown menu.
4. Change the Site Address (URL) to what you want it to be, and save the changes.

Note: You’ll need to make sure that your new domain name is registered, and that its DNS entry points to the appropriate IP address. You’ll also need to make sure that your WordPress server’s configuration is set to accept requests for the new domain name. This is something you’ll either need to handle yourself, or take up with your hosting provider.