Wills are a form of testamentary document that allow you to appoint a person or persons to administer your estate, name guardians for minor children, and specify how your estate is to be managed and distributed. However, Wills do not necessarily govern all assets or property owned at the time of death. Property owned jointly with rights of survivorship is not part of your estate at death, because there is nothing owned by you on death. Therefore it also cannot be covered by your Will.
Distribution of proceeds from plans such as RRSPs, or insurance policies, where there is a valid beneficiary designation, is not governed by the terms of your Will although the proceeds are not necessarily outside of your estate. Therefore, it is important that Wills be prepared as part of a comprehensive estate plan to ensure there are no unintended consequences.