Tips on Customizing WP Page Widget

How to Hide Wordpress Page Widgets Admin Menus

function plt_hide_wp_page_widget_menus() {
	//Hide the "Settings → Page widgets settings" menu.
	remove_submenu_page('options-general.php', 'pw-settings');
	//Hide the "Settings → Search page widgets" menu.
	remove_submenu_page('options-general.php', 'pw-search-page');
}

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

Where do I put this code?

How to Hide the "Page Widgets" Meta Box

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

	//Hide the "Page Widgets" meta box.
	remove_meta_box('pw-widgets', $screen->id, 'advanced');
}

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