a method and apparatus for forming a vertical tubular form fill package feeding the film vertically downwardly over a spout , pressing the outer lateral edges of the film together between pressure rollers , feeding joined strips of plastic zipper consisting of interlocking elements and attaching webs between the outer edges of the film and the spout , positioning guide bars on either side of the zipper between the zipper webs and sealing bars outwardly of the guide bars with the sealing bars simultaneously forming a fin seal at the outer edge and joining the zipper webs to the inner surfaces of the film between the fin seal and the spout and thereafter cross - cutting and sealing to form packages enclosing contents dropped through the spout .