Office 365 offers both browser-based and desktop versions of Microsoft Word, PowerPoint, Excel, OneNote, and more. Office 365 Web Apps allow users to view and edit Microsoft Office documents on any device via a web browser, while the desktop versions allow for offline and more robust document creating and editing.
The process that installs the new Office 365 also uninstalls all older Office products. As you might expect, the older Word, Excel, PowerPoint, and the rest of the Office suite are uninstalled to make room for the new applications. In addition, if a computer has InfoPath 2013, SharePoint Designer 2013, or certain versions of Visio 2013 or Project 2013 installed, installing Office 365 also uninstalls those programs. You won’t be able to reinstall them.