To install Office 365 or Office as a one-time purchase, visit www.office.com/myaccount on the PC or Mac that you want to install Office on. Sign in with the Microsoft account that you used to purchase, or have already associated, with the subscription or one-time purchase product, and then follow the onscreen instructions to install Office.
If you need to set up your account and install Office for the first time, visit https://setup.office.com.
For Office 365 Business subscriptions, visit https://login.microsoftonline.com.