A device is usable to feed at least one material web and/or at least one strand that is comprised of several material webs into a folding device. A superstructure is part of the device, as is a former that can be displaced in relation to the material web, and a transverse cutter which is usable to separate the material web or webs into individual products. At least one guide rail is provided in the superstructure and carries a retaining device that can be displaceably guided on the path of travel of the material web through the superstructure. A leading edge of at least one of the material webs can be attached to the retaining device. The guide rail passes the former and includes at least one flexible guide rail section whose form can be altered. In particular, the length of the flexible guide rail section can be adjusted in the region adjoining the former.