Hang tags do retail work. They show the brand, can tell a short story about the product, and carry practical details: style name, size, color, price, a barcode or SKU, and sometimes fabric or care notes. They come off before wearing, so they can be more decorative than a sewn label.
Choices include paper stock, thickness, finish, shape, die cuts, foil or embossing, and the attachment: cotton string, safety-pin loops, or plastic fasteners shot through with a tagging gun. On delicate fabric, attach the tag through a label or seam rather than open fabric, since fasteners can leave holes.
Retailers and wholesale buyers may specify the barcode type and where tags go, so check their requirements before printing. Ask whether your finishing partner can attach tags and in what position. See private label finishing and packaging.