Loan agreements, like any contract, reflect an "offer," the "acceptance of the offer," "consideration," and can only involve situations that are "legal" (a term loan agreement involving heroin drug sales is not "legal"). Loan agreements are documented via their commitment letters, agreements that reflect the understandings reached between the involved parties, a promissory note, and a collateral agreement (such as a mortgage or a personal guarantee). Loan agreements offered by regulated banks are different from those that are offered by finance companies in that banks receive a "banking charter" granted as a privilege and involving the "public trust."
A loan agreement is a contract between a borrower and a lender which regulates the mutual promises made by each party. There are many types of loan agreements, including "facilities agreements," "revolvers," "term loans," "working capital loans." Loan agreements are documented via a compilation of the various mutual promises made by the involved parties.
It is an unsaid rule in the world of loans that one needs a co-signer to ensure that the student loan gets approved. That said, it does not mean that you would not get loans if you do not have a co-signer to sign on your agreement. There are some lenders in the market who would offer loans to you with you having to worry about the co-signer.
Always obtain loan agreements in writing and read the fine print. One of the biggest mistakes borrowers make is entering into verbal agreements. If things go wrong there is no evidence to prove the case. Debtors should know the number of deferred payments, payment schedule, fees or penalties, and how the lender reports suspended payments to credit bureaus.