In the G Suite Admin Console, you are allowed to switch your primary domain to another one. As a Google Admin/G Suite Admin, you can proceed by making a decision about how to use the domain with G Suite. Some of the options available to you include adding another domain or using a domain alias.
When you decide to provide existing users with valid email addresses at the domain, you can leverage functionality associated with the option. For instance, each user will have an email address that is linked to both the domain alias and the primary domain. You are allowed to add up to 20 domain aliases and there are no additional charges levied on individual users or groups.
The email addresses at the domain alias are also available to groups. The provisions enable your users to send and receive messages from the addresses via the G Suite inbox.
This means if the primary domain you used to sign up for the service is yourcompany.com and you have another domain branch.com, you can add the second domain as an alias. Your entire staff will receive emails at both domains. Users manage messages received in the email addresses via the inbox at the primary domain – yourcompany.com.
Creating new users at a secondary or new primary domain in G Suite
The second option entails incorporating the domain as an additional domain. Doing so allows your organization to take advantage of some degree of flexibility by allocating different sets of users to each domain. You are required to pay for each G Suite user's account associated with the extra domain.
Users enjoy the benefits of having a mailbox and an email address. This option is ideal for managing several teams. Once the set up is complete, the service provider initiates the verification process before providing alias email addresses to users and groups. Depending on the size of the organization, aliases may take up to 24 hours to process.
When the domain aliases are verified and activated, messages directed to the domain alias will reach the users' inboxes. It is important that users add the new addresses to their Gmail accounts. This is a mandatory requirement for sending messages from the email addresses.
You should add all users to your business' domain via the Google Admin/G Suite Admin console.
Changing the primary domain in G Suite
As a Google Admin/G Suite Admin, you can change the primary domain for your business if the need arises. This gives you an opportunity to use another domain as your primary. The changes will be reflected in your users' emails. They will receive messages via the replacement domain.
In former editions of of Google Apps for Work and the Free Google Apps legacy edition, an admin would have to go through quite a process to swap a primary domain with secondary domain but these days it's as simple as a click.
It is important to note that you cannot switch the primary domain for free trial or legacy free edition accounts. This also applies to accounts managed by resellers and domains acquired via a Google partner. You are urged to consider alternative options before changing your primary domain. The move may lead to unexpected results
To change a primary domain that you purchased via a reseller, you are required to notify the reseller in advance. For the new domain to become active, it has to undergo verification. Once the domain is verified, you can proceed to direct emails to Google's mail servers. This can be achieved by setting up the domain's MX Records.
Additional steps include renaming users and groups to the new primary domain.