New tags (and categories) can be added via a csv ingestion, but new tag creation can be also added manually and is done in the same section as where an existing tag is manually added to an item ( track, release, playlist etc).
New tag created within a single track edit panel
Log into admin
Navigate to catalog > tracks/releases/playlists (item you’d like to add the new tag to)
Search for the item you’d like to add the new tag to
Scroll to the tags section and type the name of the tag you would like to add
If the tag doesn’t already exist, the autocomplete will show ‘Add as new tag’ select that option
Select with tag category you would like to have the new tag in and if you would like the new tag to have a parent (must be an already created tag)
Select ‘Add new tag’ the tag has now been added to the system
Save the track and refresh the page
You can now add the tag to other tracks in the same way you manually add tags to an item