Hi there! Do you mean a physical store, or an online merchant? It's fine to use a standard mobile wallet to receive Dash at a physical location, but something a little more sophisticated might be necessary to track individual customer invoices. Anypay is a good basic choice if you are using a simple phone or tablet at the point of sale. Check out the merchants section of the documentation here: https://docs.dash.org/en/latest/merchants/getting-started.html