What does the letter of credit mean?

Personal credit report.

Credit investigation is a personal credit report, which is mainly an activity of establishing credit files for individuals or enterprises through professional and independent third-party institutions, collecting and objectively recording personal or enterprise credit information according to law, and providing credit information services to the outside world according to law.

Credit investigation refers to collecting, sorting, saving and processing the credit information of natural persons, legal persons and other organizations according to law, providing credit reports, credit evaluation, credit information consultation and other services to help customers judge and control credit risks and carry out credit management activities. From Zuo Gong's Eight Years, "A gentleman keeps his word and has a levy, so his resentment is far greater than his body". Among them, "collecting by faith" means that you can verify the credibility of your words, or you can collect and verify credit.