If you are getting re-married in Ontario, you will need to bring one of the following documents when you apply for the Marriage Licence:
You can get a Divorce Certificate from the Court Office where you filed for divorce.
If you were divorced outside of Canada, you will need to obtain your divorce documentation from the country where the divorce was granted.
If you are getting re-married in Ontario and were divorced outside of Canada, you will need to follow the Foreign Divorce process.