The UTORid grants you access to many University of Toronto services, including email, USource, MRA, and Blackboard. The UTORid itself is public, so it is important that you protect your password.
Information about UTORid is available here: help.ic.utoronto.ca/category/2/accounts-and-passwords.html
You can manage your account here: UTORid Management. You can activate your account here, as well as change email preferences (e.g. forwarding, away messages).