Many blank makers sew their brand label in with a material that rips cleanly along the seam, or offer tear-away versions of popular styles. Pull it off and the neck is ready for a printed label or a sewn-in woven label. Some leave a small stub in the seam after tearing.
Removing the maker's label also removes the fiber content, origin and care information it carried. If you sell the garment under your own brand, your replacement label generally needs to cover those details. Tearing also takes care: a rough pull can stretch the neck rib or leave loose threads, so it is normally done during finishing rather than left to the customer.
Ask whether your chosen blank comes with a tear-away label, how relabeling is handled, and what your new label will say. See private label finishing.