Para usar las funciones FTP con su configuración de PHP, debe agregar la opción --enable-ftp cuando instale PHP.
La versión de PHP para Windows tiene soporte nativo para esta extensión. No se requiere cargar extensiones adicionales para utilizar estas funciones.
For some reason folks downvoted the previous entry for this, BUT... indeed, as of PHP 7, to enable this on Windows you have to add the line:
extension=php_ftp.dll
to your php.ini to resolve PHP errors that tell you PHP FTP functions are not defined; the line isn't in there (where, many things are and are just commented out).If you are using PHP 7 under Windows you have to enable ftp in php.ini with extension=php_ftp.dll.