To activate the Microsoft Office, you are required to enter the product key. You will get the product key on the basis of your Office version. In case you have purchased a retail office.com/setup, then the activation key will be available inside the package. On the other side, the key will be sent to your registered email address if you brought an online version through www.office.com/setup . Here is the full breakdown of how the client can activate the Office on the desired system.