Which technology―VBA macros, managed add-ins built with Visual Studio, or apps for Office―is the best choice for your solution? It's important to note that all three technologies will be supported in the foreseeable future. This means that if you have an existing VBA project that you are satisfied with, you can be confident your investment is safe. However, if you're looking for a new way for users to interact with Office customizations, apps for Office is a great place to start.
VBA developer documentation
The story of Office development
What are apps for Office?
Apps are web applications that extend what a document, email message, or meeting request can do in Office.
Run them in multiple environments like Office desktop applications, Office Online, and mobile browsers—in the cloud or on your site.