Any content (question, post, discussion, article) in Tribe communities can be tagged with one or more topics. Any member can select the topics of his or her post but community admins and moderators can edit/delete a topic.
If you are an admin, you can add/edit topics in the Admin Panel> Topics from left-side bar> Add Topic or edit the existing topics by clicking on [...] button. The default "type" for the topics created here by admins are Collection83.
If you are a regular user, you should be bale to create a new Tag is admins allows you to do it. Recently, Tribe added an option to the admin panel that allows admins to choose if the regular users in the community are able to create a new tag while posting a content or not. You can learn more here3.
If you choose the option "regular users can create new topic", it means that when regular users are posting a content, if they want to add a topic to their content, they can search for the related topic. If the topic they are looking for does not already exists, they are allowed to add it as a new topic (Tag2). Otherwise, regular members won't be able to add a new topic/tag.