The Sequence Classifier is one of the new features available in R8. The manual for the Sequence Classifier can be found here.
We also have a tutorial which demonstrates how to use the Sequence Classifier to classify mitochondrial sequences from kiwi (a flightless bird endemic to New Zealand) using a database of known sequences. The tutorial can be found here.
Note, the Sequence Classifier is available as a plugin and is not automatically installed in Geneious. To install this plugin in Geneious, go to Tools→Plugins, select "Sequence Classifier" from the list of available plugins and click "Install". Alternatively, the plugin can be downloaded from our website.