If there is no brand field, then the field setting is currently not set to include it in the new user wizard. To amend this, follow the below steps:
Click Configuration or Admin Menu.
Depending on how your system is set up at the top.
Click Settings and then click Field Settings.
Use the search bar to find FormData_Person_m.BrandId.
Click FormData_Person_m.BrandId then click the Include checkbox so that it is ticked.
Change the display dropdown box to Optional.
Click Save.
📌Note: Once this is done, the brand field will show in the new user wizard. However, make sure to not change the type, key or value options in this field setting, as this may produce errors within the system.