Create an Office Add-in with Napa
You can create a simple Office Add-in by using Napa.
Here's what you need to do that:
Create a basic add-in
Open Napa in your browser.
Choose the Add New Project tile.
Note: The Add New Project tile appears only if you have created other projects. If this is your first project, skip to the next step.
Choose the kind of add-in you want to create, name the project, and then choose the Create button.
The code editor opens and shows the default webpage, which already contains some sample code that you can run without doing anything else.
On the side of the page, choose the Run button ( ).
The Office application associated with the kind of add-in you chose opens, and the sample add-in appears. You can now experiment with the features of the add-in.