Manage all your domains
Does your organization own multiple domain names where you do business? Perhaps you acquired a new company or started doing business under a new name. Google, for example, owns the domains google.com, adwords.com, youtube.com, and more. If you own multiple domains, you can add them all to your Google Apps account at no extra cost. Users can then have an identity at one or more of your domains. They can share Google services as part of one organization. And you can manage all your users and domains from the same Google Admin console.
Click below for ways to add or change a domain:
Let's say your business acquires a domain for a new brand, and your users need the option of sending mail with an email address at that domain. Add the new domain to one of your existing domains as a domain alias. This gives all users in your existing domain an alternate email address at the alias domain.
Let's say you acquire a new domain for a business that has its own set of employees. To let the new employees use Google Apps services along with the users in your primary domain, add your acquired domain as a separate domain. Users in each domain will have an email address and Google account at their respective domain. And, they can find each other in global contacts, meet via Hangouts, and otherwise collaborate internally using your Google Apps services.
Let’s say users in your business or school need to share files externally. You can allow sharing with people in external organizations that you trust by whitelisting their domain as a trusted external domain. When you whitelist a trusted domain, you grant access to users of the trusted domain to the files, folders, and classes that users in your organization create. And you also allow users in your organization to receive files or share classes from users of the trusted external domain.
To use Google services with a new domain name instead of the one you signed up with, you can add the new domain as a domain alias. Users can then send mail using an address at the new domain.
You can also change one of your secondary domains to your primary domain. For details, see Change your primary domain.
You can add up to 600 domains, including 20 domain aliases, to your organization's Google Apps account. You must own the domain name and verify domain ownership for separate domains and domain aliases.