When you add a domain, a step-by-step wizard helps you add users and convert your email addresses and other services to your business name. When you complete the wizard, your business email starts coming to Microsoft instead of going to your current email provider. To learn more, see Add your users and domains to Microsoft. If you use Office 365 operated by 21Vianet, see Verify your domain.
You can add up to 900 domains to your subscription. However, you can't add a domain to Office 365 that you're already using in another Microsoft cloud service. That means that you can't add the same domain to multiple subscriptions. For more information, see Domains FAQ.
Second and third-level domains
With Office 365 Enterprise and Microsoft 365 Apps for business, you can add any level domain, including third-level domains such as marketing.contoso.com. See Add custom subdomains or multiple domains to Microsoft. If you are using Office 365 operated by 21Vianet, see Add custom subdomains or multiple domains to Office 365 operated by 21Vianet.
Domain verification and managing DNS records
With Microsoft 365, you can manage all your DNS records at your DNS hosting provider, or opt to have Microsoft set up and manage your domain's DNS records for you. If you continue to manage the records, you change specific records to point to Microsoft services as needed. For a list of domain registrars for which we provide step-by-step directions for adding the records, including the specific values to use for each record, see Create DNS records or, if you are using Office 365 operated by 21Vianet, see Create DNS records at any provider for Office 365 operated by 21Vianet.
If Microsoft manages your domain's DNS records for you, you first must switch your domain's nameserver records to point to Microsoft and then Microsoft sets up your services and then your domain's DNS records are managed at Microsoft.
If your domain is registered at GoDaddy, Microsoft can create the required records for you at GoDaddy.
No matter where your DNS records are hosted, you can set up the DNS records to use your domain for the URL for a public website hosted on Microsoft or with a different hosting provider.
Microsoft proactively checks your DNS records to find and help fix DNS issues. If your DNS records don't match what we expect them to be, you'll receive a notification in the Microsoft 365 admin center, along with information that tells you how to fix the possible issues that have been identified.
For more information, see How Microsoft manages DNS records or, for Office 365 operated by 21Vianet, see Create DNS records for Office 365 when you manage your DNS records.
Sharing a domain
You can pilot some email addresses for a domain on Microsoft, and some on your previous email provider. This is recommended only for use during a pilot, because it requires additional setup steps and has some limitations for Microsoft services. For more information, see:
To view feature availability across Microsoft 365 for business plans, standalone options, and on-premises solutions, see Microsoft 365 and Office 365 platform service description.