What is a mobile business? 

Shoppers carry mobile devices everywhere they go, and they’re using their phones to research products, and pay for things online and offline.

More information
A mobile business is a business that are not located to a particular place or address. This type of business is a sub-type of e-commerce. Examples of mobile business may be amazon, holiday autos or airbnb. The business is using services available through internet or through an app. In Wikipedia you will find a wide range of e-commerce types and examples: https://en.wikipedia.org/wiki/E-commerce