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. Hello realtors, I don't find a place in Residential Lease to add cosigner.Generally a cosigner needs to be someone who has good credit and a good rental history. Co-signer Information: If applicable, a co-signer must also complete a rental application. Collect rental Applications In Texas With Landlord Studio. When do I need a cosigner? 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. Cosigners sign the apartment lease alongside you, assuming all of the financial responsibilities associated with being a renter. The individual should have a strong financial background and credit and a high enough income to support the tenant if they fall behind on rent.