Tips on Customizing WP Last Modified Info

How to Hide the "WP Last Modified Info" Admin Menu

function plt_hide_wp_last_modified_info_menus() {
	//Hide the "Settings → WP Last Modified Info" menu.
	remove_submenu_page('options-general.php', 'wp-last-modified-info');

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

Where do I put this code?

How to Hide the "Last Updated" Dashboard Widget

function plt_hide_wp_last_modified_info_dashboard_widgets() {
	$screen = get_current_screen();
	if ( !$screen ) {

	//Remove the "Last Updated" widget.
	remove_meta_box('dashboard_last_modified_posts', 'dashboard', 'normal');

add_action('wp_dashboard_setup', 'plt_hide_wp_last_modified_info_dashboard_widgets', 20);