Pad stitch is used to hold interfacing in place within the garment, aiding structure and shape. They are permanent stitches but are invisible on the right side of the garment.
The interfacing should already be attached to the garment piece. Mark the places the pad stitches will take shape beforehand. They can be closer together or run in a curve depending on the purpose of the interfacing. For a collar, the stitches are marked closer together and curved on the collar stand but spaced further apart on the main collar piece.
Work left to right, secure thread at first pad stitch marking and take needle slightly diagonally following the markings. Create a tiny stitch perpendicular to the marked line, catching only a thread of the main garment fabric. Repeat along row to next one. Stitches will begin to form a chevron pattern.