My dad has agreed to cosign a lease with me but I am afraid my application will just be thrown out since I cannot provide a credit score or any proof of income. Learn the essential steps on how to add a cosigner to a lease to strengthen your rental agreement.A cosigner for an apartment takes on the financial responsibility for a lease. Learn how having a cosigner can help someone get approved for an apartment. A cosigner can be anyone over the age of 18 with adequate income and credit history to qualify for a rental property lease. 1. Renters of Hillsborough Township Affordable Housing units must be Low and Moderate. This guide will provide all the necessary information you need to screen, process, and add a cosigner to a lease. Your application must be filled out completely and accurately. An incomplete application may be rejected or not processed. When do I need a cosigner?