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. 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. When do I need a cosigner? So, in the event you do not qualify on your own, your landlord may ask you to get a cosigner or a guarantor to complete the rental application. 4 Easy Steps To Rent An Apartment with us: ​ 1. You can download our free application form in Word or PDF format. Once you download it, you can complete the document with all the information you need. Failure to fully complete a requested co-signer form may result in the landlord refusing a rental application. Personal Information.