When you sew a lining into a garment, a skinny piping in the seam adds a nice finish.  First prepare a skinny piping using a long 1 1/4” wide bias strip (pieced as necessary) and a narrow cord (#1) or sport-weight yarn.  A piping trim tool is handy for trimming the seam allowance to 1/4”.  Then sew the piping to the garment on the seam line before sewing the lining over.  If you sew over the stitching used to add the piping, you will not have stitches showing on the finished edge.