Tips on Customizing Notifier – Send Message Notifications Using Official API

How to Hide Notifier - Send Message Notifications Using Business API Admin Menus

function plt_hide_notifier_menus() {
	//Hide the "WANotifier" menu.
	remove_menu_page('notifier');
	//Hide the "Tools → Scheduled Actions" menu.
	remove_submenu_page('tools.php', 'action-scheduler');
}

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

Where do I put this code?

How to Hide Notifier - Send Message Notifications Using Business API Meta Boxes

function plt_hide_notifier_metaboxes() {
	$screen = get_current_screen();
	if ( !$screen ) {
		return;
	}

	//Hide the "Trigger Settings" meta box.
	remove_meta_box('notifier-trigger-data', $screen->id, 'advanced');
	//Hide the "Save Trigger" meta box.
	remove_meta_box('submitdiv', $screen->id, 'side');
}

add_action('add_meta_boxes', 'plt_hide_notifier_metaboxes', 20);