Underlay is used to stabilize an area of fabric before stitching over it. Automatic underlay is optionally available for Pattern Fill areas, Satin Areas, Satin Column, Richelieu Bars and Satin Line. To create underlay for other object types, use running stitch or single stitches.
Embroidery designs created with the ExpressDesign Wizard have an option to create underlay for the whole design.