For most universities, first-year course registration is already happening, so make sure you go and sign up for your courses as soon as possible to secure a spot in your desired time or professor or section.
The following are occasions that you need to look out for (these dates vary across universities):
Last day to cancel residence (a cancellation fee may be imposed) - Usually early August (after you receive information about which residence building you have been assigned to)
First instalment of residence and tuition fees due - Usually early August
Residence Move-in Day - Usually early September
Orientation Week - Fall 2020 may cause disruption to this event, it may be done virtually instead.
First Day of Fall 2020 classes
Last day to add or drop a class - Usually mid-September (this deadline is the last day you can drop a course you don’t like, not having it show on your transcript, and replace it with a different course; after this date, you can only drop a course, but you can no longer add a course)
Last day to drop a course without penalty - Usually after midterm season (If you drop a course before or on this day, it will indicate “Withdrawn”. If you drop a course after this date, academic penalty will apply. This course will show as Fail or NCR (no credit received) on your transcript.)
For specific university seasonal dates, please see below:
University of Toronto: https://future.utoronto.ca/newly-admitted-students/important-dates/
under "Sessional Dates", choose your campus or Faculty
under "Sessional Dates for 2020 - 2021" choose your Faculty