An edge finish is basically a really thin hem, usually found in garment sewing.  There are three different methods in creating an edge finish and you can utilize either a sewing machine or an overlock machine.  If you use an overlock machine, you can overlock stitch the edge and then fold it over to the wrong side.  You can also create the same effect by zigzagging the edge with a sewing machine.  The last method is folding a thin hem along the edge and then folding it again so that no raw edges are showing.  You will discover your preferred method and make it work for you.