You can think of AppSource is an app store for your Microsoft products. In Microsoft’s vision, AppSource is the central hub regardless of what business app you are after. You can search by industry, functionality, or application.
Generally speaking, there are two types of apps in AppSource:
Apps
Apps can be thought of as an extension to your existing Microsoft product. (Sometimes you’ll see them called Extensions or App Extensions for that reason.) An app can be a simple single purpose feature, such as address verification or a mapping tool in an Office or Dynamics product. Apps can also be bigger such as a full module and set of functionality such as shipping or warehouse management.
Solution Apps
Solution Apps are intended to cover larger industry solutions. What was previously called an Industry Vertical from a third-party vendor or Independent Software Vendor (ISV), for example, a Professional Services solution for Dynamics AX, is now a Solution App in AppSource where you can request an online trial, hosted on Azure.