You need to sign in with a Microsoft account.You need to activate Office within 180 days from the time the Windows OS is activated. (For one year subscription version only).Before you activate Office applications, Windows OS must be activated on your computer.Note: If you had activated Office already and you need to reinstall it, please click here. Before activating Microsoft 365, please check below Office regulations from Microsoft. This article describes how to activate Microsoft 365, you also can refer to the Microsoft’s Activate Office topic.