I usually do them in cross stitch. Made by ______, for _____, Pattern/design, the date of completion, and my hometown.
Then I bind two edges with the same quilt binding and attach it to the very corner of the quilt - into the binding on the other 2 sides.
I've also started putting a white or cream backing on, so they are easier to read (blocks out the print coming through the holes of cross stitch fabric.
When it is a fast quilt for a sick friend, I have put on a muslin label written on with a permanent fabric pen. OR I've printed a label off the computer onto printable fabric. That way I can add a small image or something else special.
But donation quilts to a layette distribution group or the church comfort quilts do not get a label.