Get the tools: SharePoint Hosted apps
Visual Studio includes the Microsoft Office Developer Tools for Visual Studio. Sometimes a version of the tools is released between updates of Visual Studio. To be sure that you have the latest version of the tools, run the installer for Office Developer Tools for Visual Studio 2013, or installer for Office Developer Tools for Visual Studio 2015.
Get an O365 developer subscription
There are two ways to get an Office 365 plan.
- Start with a free 30-day trial with one user license.
- Buy an Office 365 developer subscription.
MSDN getting started
https://msdn.microsoft.com/en-us/library/office/fp142379.aspx
Get the tools: Provider Hosted apps
Visual Studio includes the Microsoft Office Developer Tools for Visual Studio. Sometimes a version of the tools is released between updates of Visual Studio. To be sure that you have the latest version of the tools, run the installer for Office Developer Tools for Visual Studio 2013, or the installer for Office Developer Tools for Visual Studio 2015.
MSDN getting started
https://msdn.microsoft.com/EN-US/library/office/fp142381.aspx