Before you begin, make sure your PC or Mac meets the system requirements.
If you still don't see an option to install Office on the Office 365 Software page, it's possible your admin hasn't assigned a license to you. Find out if you have a license to install Office.
For Office 365 for home subscribers only: You can install Office on all your devices and be signed in to five at the same time. To learn more, see How sign in works in Office 365.
If you have Office 365 Home, you can share your Office 365 Home subscription with up to five family members or other people. Each person can install Office on all their devices and be signed in to five at the same time.
For a one-time purchase of Office such as Office Home & Student, Office Home & Business, or Office Professional: You can install these non-subscription versions of Office on only one computer. However, you may transfer Office to another computer that belongs to you if you experience a hardware failure or you buy a new computer. For more information, see the Microsoft License Terms for your product, or see this blog post, Office now transferable.