Purchasing Multiple Site Plans Under One Wix Account

If you have multiple sites in your Wix account, the sites are completely separate from one another. They have no connection other than the fact that they can be edited from the same Wix account or shared workspace. 

A site plan cannot be used for multiple sites. Each site you want to upgrade must have its own Premium or Studio site plan. If you wish to apply premium features, such as connecting your own domain, to more than one site, you must purchase additional upgrades.

There is no limit to the number of Premium or Studio plans you can add to your account. There is also no limit to the number of sites you can create under a single account.