A co-applicant is not required to apply for a home loan, but it can increase your chances of approval and allow you to obtain a larger loan amount. A co-applicant is typically a spouse, parent, or child who joins the loan application and shares responsibility for loan repayment with the primary borrower. If the primary borrower has a low credit score, insufficient income, or the property is jointly owned, the lender may also require a co-applicant. However, having a co-applicant may affect both parties loan eligibility and creditworthiness.