Microsoft Store) without physical disc, your product key is stored in your Microsoft online account or arrived in your email receipt. Method 1: Find Office 2016 / 2019 Product Key from Microsoft Account Lost your Office 2016 product key? How can I backup or transfer Office activation to another computer? If you need to reinstall Windows or Office but you’ve lost 25-character product key, here are all possible ways to find Office 2016 / 2019 product key, or backup your Office activation so you can restore it later.
