Visual Studio Add-Ins vs. Shared Add-Ins
There are two different Add-in project types: Visual Studio and Shared.
A Visual Studio add-in can be loaded into both Visual Studio and the Visual Studio Macros IDE. Conversely, a Shared add-in can be loaded only into Microsoft Office applications such as Microsoft Word, Microsoft Publisher, Microsoft Visio, and Microsoft Excel. Also, each type offers a different set of options. For example, the Visual Studio Add-in Wizard allows you to:
Create a command bar user interface (UI) for your add-in,
Define when the add-in loads, and
Insert information into the Visual Studio Help About box.
The Shared Add-in Wizard only allows you to:
Specify whether the add-in loads when the host application (that is, the Office application) loads, and
Specify whether the add-in is available to all users of the computer or only the person who installed it.
In short, create Shared add-ins for use in Office applications, and create Visual Studio add-ins for use in Visual Studio.