Office Developer Tools
The Office Developer Tools are a set of Visual Studio project templates.
VSTO can interact directly with the Office applications via the Primary Interop Assemblies (PIAs).
The .NET Framework version that your project uses must be installed on the end user computers.
For example if your solution targets .NET Framework 4.5 then this must be installed.
The two most important factors when creating a VSTO solution are the version of Office you are targetting and the version of Visual Studio that you want to use.
For a VSTO solution to work there are a number of prerequisites that must be installed first.
For more information on exactly what features are available in the different versions of Visual Studio, please refer to the Visual Studio Editor > Versions page.