I have attached them before and after finishing the quilt.
The last one I put my name and date on a border that I put around the Overall Sam Quilt with my little quarter inch alphabet on new machine. I did that after I was done. It is sewn through all the layers as it was already quilted when I thought about it. You can read it, but not overly bright, so that it just blends right in and dark enough for it to be read.