A guarantor is a person or a company who will co-sign on your lease in case you do not qualify to rent an apartment in New York on your own. The ultimate guide on how to secure your dream apartment with a guarantor.Your guarantor will fill out an application and provide similar documents to a landlord as you, including photo ID and recent bank statements. Complete an application without omissions or falsifications,. Meet all of our remaining qualifications, and. Learn more about New York rental applications and download our free PDF form. Screen prospective tenants with Avail landlord software. A guarantor must fill out an application, provide income documentation, have their credit pulled, and sign your lease. Please read our application criteria and community policies below. Applicant(s) must have a legal, verifiable source of income.