A method for setting and controlling an apparatus for preparing mail pieces from postal items, the method comprising a setting stage and at least one subsequent operating stage during which the apparatus prepares mail pieces in accordance with settings established during the setting stage, the setting stage comprising: a scanner (19, 20) of the apparatus scanning at least a portion of the postal item (2, 25); storing image data representing an image of the scanned portion of the postal item (2, 25); displaying the image represented by the image data on a display, the displayed image containing a mark; selecting an area of the displayed image containing the mark; generating, from the image data representing the selected area of the displayed image, a mark data set representing at least the mark; storing the mark data set; inputting instruction data representing at least one mail preparation instruction; and storing the inputted instruction data in association with the mark data set; and the operating stage comprising: feeding at least one postal item (2, 25) for inclusion in a mail piece to the scanner (19, 20); the scanner (19, 20) scanning item image data representing an image of the scanned portion of the postal item (2, 25); comparing the scanned item image data with the mark data set; in response to agreement between the scanned item image data and the mark data set, selecting instruction data stored in association to the mark data set from the inputted instruction data; and the apparatus preparing the mail piece including the scanned postal item (2, 25) in accordance with the selected instruction data. a scanner (19, 20) of the apparatus scanning at least a portion of the postal item (2, 25); storing image data representing an image of the scanned portion of the postal item (2, 25); displaying the image represented by the image data on a display, the displayed image containing a mark; selecting an area of the displayed image containing the mark; generating, from the image data representing the selected area of the displayed image, a mark data set representing at least the mark; storing the mark data set; inputting instruction data representing at least one mail preparation instruction; and storing the inputted instruction data in association with the mark data set; and the operating stage comprising: feeding at least one postal item (2, 25) for inclusion in a mail piece to the scanner (19, 20); the scanner (19, 20) scanning item image data representing an image of the scanned portion of the postal item (2, 25); comparing the scanned item image data with the mark data set; in response to agreement between the scanned item image data and the mark data set, selecting instruction data stored in association to the mark data set from the inputted instruction data; and the apparatus preparing the mail piece including the scanned postal item (2, 25) in accordance with the selected instruction data. feeding at least one postal item (2, 25) for inclusion in a mail piece to the scanner (19, 20); the scanner (19, 20) scanning item image data representing an image of the scanned portion of the postal item (2, 25); comparing the scanned item image data with the mark data set; in response to agreement between the scanned item image data and the mark data set, selecting instruction data stored in association to the mark data set from the inputted instruction data; and the apparatus preparing the mail piece including the scanned postal item (2, 25) in accordance with the selected instruction data.