I make embroidered labels. Usually I use a leftover block backed with some of that tear-away stuff.
It was suggested to me some time ago, if at all possible to put the label on before quilting, it makes it more permanent.
I like to put the name of the quilt, who made it (me), significant name and date of the person receiving it, and the quilter, if need be. I just finished a baby quilt and had to gift it before the baby was born. I gave the blank label to the mother-to-be with an explanation that it will be filled after the baby is born.
BTW, adorable quilt!