A drywall finishing system for finishing 1) normal inside and outside corners of any angle, 2) stub wall or closet corners, 3) window wrap corners, and 4) L-metal for window sills and areas where drywall ends against some other surface like brick. The finishing system comprises a preformed trim piece comprising a semi-rigid member that is relatively thick in the center and tapers laterally to a thin edge. A layer of paper is bonded to the inside surface of the semi-rigid member for receiving joint compound to continuously bond the trim piece to the dry wall; this paper layer can optionally have a layer of adhesive material on its outer surface. A layer of finishing material is bonded to the exterior surface of the semi-rigid member.