I take a piece of plain fabric like muslin, iron it to freezer paper, write using a fine point permanent marker like Sharpie ultra fine. I include the name of the recipient, date, occasion, my name as the quilter. Sometimes I just put the name of the pattern, date completed (month and year at least) and my name. My first machine quilted quilt with feathers has a label that reads "First Feathers" the date & my name. Years from now I have a record of when I started doing feathers and I'll see my progress. I set this label in a corner on the backside of the quilt before I complete the binding. Tear off the freezer paper, Turn under two edges and applique then finish the binding over the other two edges. I wish I had done this from the start. I have quilts I made probably 20 or so years ago but I don't know for sure because I didn't label them.
Hope this helps explain it.