mobile app for purchase orders

We are a manufacturer that deals in B2B transactions with established companies. We are looking for an order placing app. Currently, our clients place their orders by phone. We want our clients to have the able to login to our website, enter their password then proceed to placing their order. An existing client that is preapproved for credit should only have to enter a minimal amount of information. Their information should be pre loaded so they do not have to re-entered each time they login. Our clients will usually order or reorder the same product(s) when they need them. 90% of the time the client will reorder the same product each time. Exceptions may be that the client may want to increase or decrease the quantity of product they wish to order ( 2 items vs 1 item or vise versa). They must have the option to change the number of items they want to order. Some of our clients have multiple 'ship to' locations. They must have the ability to easily choose from a list of pre determined 'ship to' locations as opposed to having to type in the address each time they order a product. Once the order is entered, they can submit to us for processing. Being that they have already been pre approved, their is no need to process credit cards. After the client has submitted their order, we want to receive 1) a purchase order. 2) packing slip showing what the client has ordered that will be included with the shipment. 3) generate a shipping label that will be used to ship the product using our FedEx account. At some point in time, we may offer our products for retail sales which would require a shopping cart but that will be decided later this year.