An Office 365 product key uses a combination of 25 letters and numbers, and looks like this: XXXXX-XXXXX-XXXXX-XXXXX-XXXXX. Your Microsoft Office 365 product key could be 1) On a card inside of the Office 365 box you bought at a store, 2) On the back of a subscription card, 3) On an email receipt or possibly embedded in the install link (if you downloaded Office 365 from an online store)

For more tips like this, check out the working remotely playlist at www.youtube.com/FoetronAcademy . Also, if you need any further assistance then you can raise a support ticket and get it addressed.