Open the artwork that you want to print on your computer.
Print out a preview of the design on standard white paper. If necessary, resize the image and print it again until it appears the way that you want.
Flip the image if necessary. The design will be reversed when you iron it on the shirt, so if the direction of the image is important (such as text), flip it.
Print the image on an iron-on transfer sheet and let the ink dry thoroughly.
Cut the design out of the paper, leaving a 1/4-inch border around the edges.