So you are talking about the green checkmark next to the account name, this is done via a publisher vetting process (which is actually for proven upstreams) … @Igor is usually the person handling this … it will also involve to link to your public website and to use a company email address for the account.
(and i’ll move you out of the devices category where i moved your post because the name “brand account” usually refers to UbuntuCore images)