Site Admin can add new brands for the Classified plugin, follow the steps below for more details.

(Back-end)
Access Admin Dashboard => Plugins Manager => Classifieds => Brands tab

Click the Add New Brand button => Show the popup.

Enter the brand name and then click the Save button. Now the new brand has been added successfully.

And can change brand name with many languages by editing brand:

(Front-end)

When a member enters a value in the Brand field on the Post New Listing page, the system will automatically suggest for Brand.