How to Hide onOffice for WP-Websites Admin Menus

function plt_hide_onoffice_for_wp_websites_menus() {
	//Hide "onOffice".
	remove_menu_page('onoffice');
	//Hide "onOffice → Getting started".
	remove_submenu_page('onoffice', 'onoffice');
	//Hide "onOffice → Addresses".
	remove_submenu_page('onoffice', 'onoffice-addresses');
	//Hide "onOffice → Estates".
	remove_submenu_page('onoffice', 'onoffice-estates');
	//Hide "onOffice → Forms".
	remove_submenu_page('onoffice', 'onoffice-forms');
	//Hide "onOffice → Settings".
	remove_submenu_page('onoffice', 'onoffice-settings');
}

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

Where do I put this code?