The Extensibility projects templates in the New Project dialog box enable you to create add-ins, which are extensions that add functionality to the Visual Studio integrated development environment (IDE).
The Extensibility project templates create add-in projects. You can create two types of add-ins:
Visual Studio Add-ins — A Visual Studio add-in works only in Visual Studio and Visual Studio Macros environments.
Shared Add-Ins — In addition to working in Visual Studio and Visual Studio Macros environments, a shared Add-in also works in Microsoft Office applications, such as Microsoft Word, Microsoft Visio, and Microsoft Excel.
To open the New Project dialog box:
On the File menu, point to New, and then click Project.
Expand Other Project Types and click Extensibility.
The add-in project templates appear in the Templates pane.
Selecting either project starts the Add-In Wizard where you can select:
The programming language in which to create the add-in.
The application hosts, either Visual Studio or Visual Studio Macros.
Other add-in options such as add-in name, description, command-bar UI, load behavior, and Help About information.