insert a taxonomy for a custom post type

You can do this by hooking into the save_post action. As save_post is fired for every post type and on update/publish/autosave etc., you need to add a few conditionals to avoid your terms being added multiple times and/or for inappropriate post types.

You should also have a method of checking if your terms have already been added, to avoid complications – for example you manually remove ‘latest’ from one job, and update it, it should not be set again.

I do this by setting a post_meta, defining that I already added the terms.

So, alltogether, with the checks for post type, revision, and already added terms this could look something like this:

add_action( 'save_post', 'f711_save_post' );
function f711_save_post( $post_id ) {
    // return on auto-save and on other post-types
    if ( wp_is_post_revision( $post_id ) || $_POST['post_type'] != 'jobs' )
        return;

    // check if the taxonomies have already been added
    if ( get_post_meta( $post_id, 'f711_check_tax_added', true ) == 'added' )
        return;

    // insert the new terms
    wp_set_object_terms( $post_id, array( 'latest', 'active' ), 'jobs_taxonomy_genre' );

    // set the post meta so the terms do not get added again
    update_post_meta( $post_id, 'f711_check_tax_added', 'added' );
}