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."
For commercial banks and large finance companies, "loan agreements" are usually not categorized although "loan portfolios" are often broadly characterized into "personal" and "commercial" loans while the "commercial" category is then subdivided into "industrial" and "commercial real estate" loans. "Industrial" loans are those that depend on the cashflow and creditworthiness of the company and the widgets or service that it sells. "Commercial real estate" loans are those that repay loans but that depend on the rental revenues paid by tenants who lease space, usually for extended times. More granular categorizations of loan portfolios exist but these are always variations around the larger themes.
The content of the loan agreement includes the precise details of the agreement that has transpired between lender and debtor. Not only that, the agreement should also consider the standard government laws that is already in effect or established. Since the laws were created to protect all people, it is beneficial to both parties concerned.
Whatever is agreed regarding applicable penalties for late or inability to comply should not only be discussed but also defined. Payment deadlines also should be set and included in the loan agreement as well. In order to effectively carry out the terms in the agreement, it is but proper to include the contact information of both the lender and debtor should the need arise to call them out.