After installing Office 365, you will also need to open an application (shown here with MS Word) and log in with Duo Two-Factor authentication in order to activate Office 365.
Microsoft Office 2016 applications (e.g., Word, Excel, etc.) will be replaced with updated versions once Office 365 is installed. MiWorkspace Macs running macOS 10.14 or higher can download and install Microsoft Office 365 from the Managed Software Center.