I sold big quilts for many years, now I just do small ones. But, when I did a large one, I always just hand embroidered my initials in a corner on the back, about 1/2 inch high letters. It gave it the homemade touch. For special order wedding quilts, I added the year. Now for my small quilts, I print out my logo on the iron on sheets made for printers and I iron it on and sew around the edge. It's about 1" x 1-1/2" (which I also use on my bags and jewelry cases in my shop). Years ago I bought large labels and they just seemed to ruin the design so I never used them.