A supply station for positioning enclosures on an enclosure-collating path of a mail-processing installation allows a simple conversion from operation for processing a stack of comparatively flexible, thin enclosures to operation for processing a stack of comparatively thick, essentially inflexible enclosures. The conversion is achieved using a magazine housing inside a supply station housing mounted so that it can be secured in two different pivot positions, whereby in one pivot position the lowermost enclosure of a stack of enclosures is bent using a vacuum arrangement in which the front end of the enclosure in the withdrawal direction can be gripped by a gripper, while in a second pivot position of the magazine housing, the front end in the withdrawal direction of a lowermost, comparatively thick and essentially inflexible enclosure is pushed by means of a pusher arrangement directly into the open claws of the gripper.