They make a prepackage fabric that is treated and already affixed to paper. Fabric stores and quilt shops carry it.
You load it into your printer one sheet at a time, and follow the directions on the package. It will print directly onto the fabric. :D:D:D
If you want to use your own fabric, cut sheets of freezer paper the same size as your copy paper. Cut the fabric slightly larger. With a dry iron the freezer paper's waxy side to the back of your fabric, then trim the fabric to the same size as your paper. It can be run through the copier then.
Just make sure your fabric has been washed, dried and pressed well. Do not use any fabric softener in the washer or dryer, or the ink will not penetrate the fabric as well :D:D:D