How to Hide Velnix Form Monitor Admin Menus

function plt_hide_velnix_form_monitor_menus() {
	//Hide "Form Monitor".
	remove_menu_page('vfmo-monitor');
	//Hide "Form Monitor → Dashboard".
	remove_submenu_page('vfmo-monitor', 'vfmo-monitor');
	//Hide "Form Monitor → History".
	remove_submenu_page('vfmo-monitor', 'vfmo-history');
	//Hide "Form Monitor → Settings".
	remove_submenu_page('vfmo-monitor', 'vfmo-settings');
}

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

Where do I put this code?