I make my own labels, using either muslin or some other light fabric or one of the fabrics in the quilt front. The size goes according to what I want to put on it. I hand write or print my information (who it was made for, made by, quilted by, occasion, date, etc. - whatever is appropriate), always using a black permanent fabric pen. Sometimes I'll write out the information on a little larger piece of fabric and trim it down to label size so I know I got all the information on. I then turn under the edges and hand stitch on the bottom left corner of the back. Sometimes I embellish the label with other colors of ink.