If you don't have a longstanding credit history, you may need someone with good or excellent credit to co-sign your loan. A co-signer takes on loan responsibility, serving as a guarantor, and is required to make loan payments if you're unable to. Keep in mind that your loan repayment history will affect your co-signer's credit score. With a joint-applicant loan, both applicants are held equally responsible for paying the loan back. A co-applicant has more rights and responsibilities than a co-signer.