Account administrators can submit verifications for all email domains associated with their organization. This prevents new Amazon Business accounts from being created in your organization’s name. If anyone attempts to create an account with the verified domain, they will be notified that they need to join the official account instead.
Once a domain is verified, you can consolidate any other accounts that are using the same email domain. You’ll need to invite administrators from the other accounts to join your official Amazon Business account to start the merging process.
To add a domain, account administrators can go to their Business settings > Domain verification.