Office 365, Email, Exchange, How to access your account via the Outlook on the Web client
How do I access my Exchange account through a web browser?
You can log in to your Exchange account at: https://outlook.office365.com. On the Outlook Sign in page use your entire University email address NetID@illinois.edu. This will open an Illinois branded login page where you enter your entire University email address NetID@illinois.edu and NetID password. Then click the Sign in button. If you've protected your account with DUO, then you'll be prompted to authorize the access.
If you need to reset your password go to: https://go.illinois.edu/password