The classic sales process implies that your clients place an order in your app and then pay you online. This is indeed a very common option and fully feasible in your GoodBarber app thanks to payment gateways.
But in the case of local delivery, there are other options available to you, such as offline payment.
When creating your shop, keep in mind that it’s possible to offer online or offline payments, or both, to maximize your chances of meeting the needs of a maximum number of clients.