Go to www.office.com/myaccount and choose My account. If you’re prompted to, sign in with the email address and password you used to set up Office. If you can’t remember which email address you used, see I can't remember the Microsoft account I use with Office.
If you’re installing for first time, you might not have an account page yet. You’ll set that up as a part of installing Office.
What’s on the My Account page?
If you have an Office 365 subscription, on your My Account page you can also:
share your subscription (Office 365 Home only)
manage your account
access services like Skype and OneDrive
get help and support