Making Decorative Pillows Is There An Iron-on Type Of Material That Can Be Adhered To The Back Of Fabrics To Thicken The Fabric?

Is there an iron-on type of material that can be adhered to the back of fabrics to thicken the fabric? - making decorative pillows

I bought to make cloth, cushion covers decorative, but the material is very thin. Is not it something as iron at the rear of tissue that hardens a little? If so, what is the appeal? Another idea, which is twice the stuff? Thank you!