The form is available at the following link, www.mah.gov.on.ca/Page18704.aspx The Ontario lease must contain the following data: The contract must be signed by the landlord and tenant. It is completely legal for the tenant to allow someone to move in with them without telling the landlord who that person is. You can only collect information about the person if the tenant wants to add them to the lease and make them responsible for paying the rent, and at this point you could check them out like any new rental applicant. If both parties sign the lease, it is kept for the duration of the rent for the personal minutes of each party. A rental agreement also protects both parties from future misunderstandings, for example who arises for damage to the rental property. The written lease proves that both parties have recognized and acknowledged the terms agreed upon therein.