If you already have a website with your domain that is hosted outside Office 365 operated by 21Vianet, it doesn’t move to Office 365 when you add your domain. You can keep hosting your website where it is, while you use Office 365 to host your email as well as use team sites, instant messaging, and so on. In the domains setup wizard, choose Yes when asked if you have a website you currently use.
Note: To learn how you get started using your domain with Office 365, see Verify your domain in Office 365. We’ll show you the steps the domains setup wizard includes that guide you through adding your domain to your Office 365 subscription, changing your email address (which is also your user ID for Office 365) to use your domain name, and setting up your users’ email addresses with your domain.