Office Add-ins can do almost anything a webpage can do inside a browser.
Your solution can run in Office across multiple platforms, including Windows, Mac, iPad, and in a browser. With Office Add-ins, you can use familiar web technologies such as HTML, CSS, and JavaScript to extend and interact with Outlook, Excel, Word, PowerPoint, OneNote, and Project. You can use the Office Add-ins platform to build solutions that extend Office applications and interact with content in Office documents.
