Embroidery Backing

Embroidery backing (also called stabilizer) is a material placed behind the fabric you're embroidering to provide support and stability during stitching. It helps keep the fabric from stretching, puckering, or shifting, which results in cleaner, more professional-looking embroidery.
Embroidery puff foam—often just called puff foam—is a type of material used to create 3D or raised embroidery designs, commonly seen on caps, jackets, and other items where you want a bold, dimensional look.
There are several types of embroidery backing, and the best one depends on the fabric and design you're working with:

Cut-Away Backing                        Tear-Away Backing                  Wash-Away Backing

  Sturdy and permanent.                   Temporary.                                    Dissolves in water.