I learned from somewhere, perhaps here, to sew my label into the seam of the binding as mentioned above. Rationale was to keep the label in place for the life of the quilt, it is harder to take the label off and steal the quilt (Yes, we all think this would not happen to us, but it does.) and to simply save time.
I use a 4.5" square of white or off white fabric folded on the diagonal, write on the information, sew it into the seams of one corner of the quilt on two sides, then finish stitching the binding on as usual. Lastly, I hand stitch the one side with tiny stitches. And yes, I leave the square doubled to avoid the shadowing of the backing print underneath. This has worked for me for 20 plus years. Occasionally, I will write directly onto the quilt in the corner but not often because of the print or color of the back.
Obviously, wash after the label is securely on the quilt.
