You need to sign up or sign in to your Office account because it gives you the opportunity to manage your subscriptions in one place. Without having a office my account, you won’t be able to download your subscription and carry forward the task of deploying Office. Using this account, you can change the billing information of your account as well as cancel it. All in all, your account is a one-stop solution for doing anything related to Office. Also, if you wish to reinstall your product, then you will need an account from where you can get hold of all your purchased Office products.