Equifax, Experian, and TransUnion are three of the major credit reporting agencies. Their primary function is to compile credit reports on individuals. These agencies collect information about individuals' credit histories, including details on credit accounts, payment history, outstanding debts, and public records, and they provide this information to lenders and other authorized entities.
While they do not directly decide whether to approve or reject a loan application, lenders use the credit reports generated by these agencies, along with other factors, to make lending decisions. They also provide information and tools that can help individuals understand and improve their credit scores, but the credit agencies themselves do not directly help improve scores. They mainly serve as a source of credit information.