I used to hand stitch them onto the back, preferably in conjunction with the binding. But... it's been a long time since I put a label on a quilt. :o

I hand stitch them on after all else is done. That way I can take maximum time to determine what to put on them!!

I usually place my label in a lower corner, so I do an extra step, and "bind" the label on the top and one side. Then I sew the other two sides of the label onto the quilt while I'm sewing on the binding. I hand sew down the "bound sides of the label when I am sewing down the binding.

Also, if you know you are going to need a hanging sleeve on your quilt, sew the sleeve in while you are sewing on the binding, then sew the binding down on top of the edge of the sleeve. That way, you only have to sew one edge of the sleeve down by hand instead of both.

I stitch mine in on 2 sides while doing binding then hand stitch the other 2 sides by hand

Thank you so much for your answers. I have an embroidery machine now so I'd like to put my labels on my quilts. When I first started quilting I would use a marking pen & handwrite on the back of the quilt. I had gotten away from quilting & have started to do it again.
Thanks again for all your tips,
Marilee