How to Hide WP Authenticator Admin Menus

function plt_hide_wp_google_authenticator_menus() {
	//Hide the "Users → My Apps Passwords" menu.
	remove_submenu_page('users.php', 'wpga_apps_passwords');
	//Hide the "Settings → Authenticator" menu.
	remove_submenu_page('options-general.php', 'wpga-settings');
}

add_action('admin_menu', 'plt_hide_wp_google_authenticator_menus', 11);

Where do I put this code?