Abstract: Electronic information input via an input means is divided into first and second groups e.g. representing information which may not be modified except by a skilled operator, and information which may be modified freely. The information is stored in an information file and display elements are stored in e.g. a related information file. If a request for modification of one of the information elements is input via the input means, a judging means determines, on the basis of controlling information in a controlling information area, whether the information element belongs to the first or second group. If it belongs to the first, a display means displays one of the display elements as e.g. a warning to the operator that the information element may be modified only by a skilled operator. A password system may be provided to identify such a skilled operator.