Some embroider on a separate piece of cloth. Some use permanent marker. I have a friend who is visually impaired and her niece uses French knots for Braille to label quilts for her. She also hand embroiders around the edges information to label. Many different ways to label. I've labeled right on the quilt itself by hand embroidering. Some machine embroidery. Some have others do it for them. You can Google quilt labeling and they have many ideas.