You can create a Taxonomies using the add helper method, and passing in a name. A slug of the name will be created for you.
Taxonomy::add('Foo');You can create a term with an alternative slug by passing in a data array, the same as using the create helper method.
Term::add(['slug' => 'bar', 'name' => 'Foo']);You can find unassociated Term records or create a new one and add them to a taxonomy using addTerms:
$taxonomy->addTerm('Foo');
$taxonomy->addTerms(['Foo', 'Bar']);