I label all my quilts and the ones I make for donation through my Guild are labeled with the Guild label. For my personal ones I make a label on my computer and print it out on my printer and heat set the ink. It will withstand many washings this way. I get high thread count fabric at the fabric store and iron it on to freezer paper to run it through the printer. I have also used permanent ink pens like Micron or Tulip and wrote the label.