How do you create a custom taxonomy in WordPress?

To create a custom taxonomy in WordPress, follow these steps:

• Open the functions.php file in your WordPress theme's directory.
• Add the following code to register a new taxonomy:

  function custom_taxonomy() {
  $labels = array(
    'name'                       => 'Taxonomy Name',
    'singular_name'              => 'Taxonomy Singular Name',
    'menu_name'                  => 'Menu Name',
    'all_items'                  => 'All Items',
    'parent_item'                => 'Parent Item',
    'parent_item_colon'          => 'Parent Item:',
    'new_item_name'              => 'New Item Name',
    'add_new_item'               => 'Add New Item',
    'edit_item'                  => 'Edit Item',
    'update_item'                => 'Update Item',
    'separate_items_with_commas' => 'Separate items with commas',
    'search_items'               => 'Search Items',
    'add_or_remove_items'        => 'Add or remove items',
    'choose_from_most_used'      => 'Choose from the considerable used items',
    'not_found'                  => 'Not Found',
    'no_terms'                   => 'No items',
    'items_list_navigation'      => 'Items list navigation',
    'items_list'                 => 'Items list',
    'back_to_items'              => 'Back to items'
  );
  $args = array(
    'labels'                     => $labels,
    'hierarchical'               => true,
    'public'                     => true,
    'show_ui'                    => true,
    'show_admin_column'          => true,
    'show_in_nav_menus'          => true,
    'show_tagcloud'              => true,
    'rewrite'                    => array( 'slug' => 'taxonomy' )
  );
  register_taxonomy( 'taxonomy', array( 'post' ), $args );
}
add_action( 'init', 'custom_taxonomy', 0 );

• Save the functions.php file.
• Go to your WordPress admin panel and click on 'Posts' or 'Pages', depending on the post type you assigned your taxonomy to.
• Click on 'Add New' or edit an existing post/page.
• In the right sidebar, you should now see a box labeled with the name of your taxonomy. You can add new terms by clicking the '+ Add New Taxonomy' link.

That's it! You have now created a custom taxonomy in WordPress.