The card does not say directly whether the pencil can be used on the nails of the hands and the feet at the same time. It describes a solution pencil for nail care that is applied to the whole surface of the nail and advises not washing the feet for several hours after application. The card says nothing about the nails of the hands.
General information (not a manufacturer's instruction): if you want to use the product on different nails, check this on the packaging or with a doctor.