A lot depends on your printer. There are different techniques for the different type. You can send out to Spoonflower or other places, that means a lot of things have already been taken care of. Some people with better handwriting and/or embroidery skills than I do them that way.
You can buy prepared sheets of white fabric -- check out your local office supply store in the special stuff section, it is generally less expensive than buying at the LQS or online through quilting stores.
I've been printing on fabric since about Y2K. I have used many different fabrics, solids, colors, and prints simply by ironing the fabric to freezer paper, cutting nicely to size and running through my correct printer path. I've had to do things, again, whether it was ink jet or laser or whatever.