You mustn’t exceed the permitted duration of stay in Canada without having applied for a change in status. You must also comply with the various conditions like duration of the study, restrictions on work, and maximum workable hours.
You must review your study permit cautiously and familiarize yourself with all the rules it has. You should apply for the renewal before the expiry of current status else you may need to leave Canada.
When the renewal or a change of status application is submitted before the expiry of current status, then you are in implied status, which is like a temporary resident. The proof of the submission of the status change application should be kept safe.
If you lose status in Canada due to failure in compliance of the study permit conditions, you may file for the respiration within 90 days of status loss.