Iron-on material or heat transfer vinyl (HTV) is used to add designs to T-shirts, sweatshirts, backpacks, pillows, and more. There is one very important thing to remember before cutting iron-on material: always flip or mirror the design. All cutting machine software allows you to do this before cutting. After loading the design, select the entire design and "flip" it or mirror it. That way, when it cuts, the design will read correctly when laid flat and ironed onto the fabric. In Cricut Design Space, for example, this feature is called "Flip." Click Flip and then click Flip Horizontal.