How to Hide WhatsLink Click Tracker Admin Menus

function plt_hide_whatslink_click_tracker_menus() {
	//Hide "WhatsLink Click Tracker".
	remove_menu_page('whatslink-click-tracker');
	//Hide "WhatsLink Click Tracker → WhatsLink Click Tracker".
	remove_submenu_page('whatslink-click-tracker', 'whatslink-click-tracker');
	//Hide "WhatsLink Click Tracker → Settings".
	remove_submenu_page('whatslink-click-tracker', 'whatslink-click-tracker-settings');
	//Hide "WhatsLink Click Tracker → Upgrade".
	remove_submenu_page('whatslink-click-tracker', 'whatslink-click-tracker-upgrade');
}

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

Where do I put this code?