How to install Microsoft Office 365 on Windows desktop

Go to www.office.com and if you’re not already signed in, select Sign in.
Sign in with the account you associated with this version of Office. This account can be a Microsoft account, or a work or school account.
From the Office home page select Install Office.
This completes the download of Office to your device.
Depending on your browser, select Run (in Edge or Internet Explorer), Setup (in Chrome), or Save File (in Firefox). If you see the User Account Control prompt that says, Do you want to allow this app to make changes to your device? select Yes. The install begins.
Your install is finished when you see the phrase, “You’re all set! Office is installed now” and an animation plays to show you where to find Office applications on your computer. Select Close.

Activate Office

To open an Office app, select the Start button (lower-left corner of your screen) and type the name of an Office app, like Word. If you have Windows 8.1 or 8.0, type the name of an Office app on the Start screen.
To open the Office app, select its icon in the search results.
When the Office app opens, accept the license agreement. Then, Microsoft Office is activated and ready to use.