If you wish to transfer out your Business Mailbox from Tailor Brands so that it will be managed directly by Google, you can terminate the plan with Tailor Brands, and then set it back up with Google.
To terminate your plan, please contact our Support Team at contact@tailorbrands.com. After we terminate the plan on our end, you will receive an email from Google to add your payment details. If you are not seeing the email in your main inbox, be sure to check your Spam and Promotional email folders. Alternatively, you can follow the steps provided here.
Once you add your payment details, you will be simply asked by Google to complete the registration process on their end directly.
This transfer process can also be used if you want more storage space, access additional features, or sign up for other Google Workspace editions.