San Francisco based Uber has operations in over 900 metropolitan areas. Uber uses a dynamic pricing model; prices vary according to supply and demand at the time of service. However, customers are quoted the fare or delivery fee in advance. Service is generally accessed via mobile app. Users set up a personal profile with a name, phone number, other information, and payment preference, which could be a credit card, e-commerce payment system or, in some cases, cash. After the service is complete, the customer may be given the option to provide a gratuity to the driver, which is also billed to the customer's payment method. In August 2014, Uber launched Uber Eats, a food delivery service.