I hand print information on a piece of muslin or white fabric and sometimes I draw a little picture as well. I use the pigma pens that are sold at quilt shops. Then I fold in the edges and hand stitch it to the back of the quilt after it is quilted and the binding is sewn on. I tell the block name, the date or year it was made, who made it, who quilted it, how to wash and dry it..... and sometimes I include the name of the person I made it for or the occasion.
Yes, you have to put a label on..... otherwise, after you're gone, someone will wonder..... who made this quilt, when was it made, how do I care for it???? A label answers all those questions.