When you sign up for Google Apps, you give the name of the Internet domain for your organization. This domain name becomes the primary domain associated with your Google Apps account. As the account administrator, you'll use the primary domain name to sign into the Google Admin console for your account.
When your organization owns multiple domain names, you need to choose one to be your primary domain. Choose carefully, because it is difficult to change once your account is established.
We recommend that you choose the domain that serves as your primary business identity for messaging and collaboration. In most cases, this domain is the domain for the parent corporate business unit or top-level organization.
We recommend that you sign up for Google Apps with this primary domain rather than a temporary or test domain, even if you plan to run a pilot program before rolling out Google Apps. You can add an additional domain to your Google Apps account for use during testing or a pilot.
Selecting a domain name is a lot like selecting a username for your email account. If your name is Bradley Baker, you might select bbaker, bradb, bradley, bakerb, or bradbaker. It might also depend on what's available. If bbaker is already taken, you could choose bbaker2.
When you're picking a domain name, you should pick a name that represents you, or your organization. We'll let you know if it's already taken in the Domain Name System (DNS). If the domain name you picked isn't available, we'll offer you a list of variations that you might like. A common variation is to change the top-level domain (ex. If you pick bradbaker.com, we might suggest bradbaker.net). You can also try another name.