In general, you can embroider on any fabric. Cotton, wool, linen, felt, or even denim and leather, can be used as a canvas for creating beautiful embroidery. However, keep in mind that thicker fabrics require sturdier needles, and thinner fabrics have a tendency to pucker when stitching bold embroidery letters or filled in shapes. When in doubt, stick with cotton or linen-cotton blend fabrics with a medium weave.