A letter of credit adds a bank's promise to pay the exporter to that of the foreign buyer provided that the exporter has complied with all the terms and conditions of the letter of credit. The foreign buyer applies for issuance of a letter of credit from the buyer's bank to the exporter's bank and therefore is called the applicant; the exporter is called the beneficiary.

Payment under a documentary letter of credit is based on documents, not on the terms of sale or the physical condition of the goods. The letter of credit specifies the documents that are required to be presented by the exporter, such as an ocean bill of lading (original and several copies), consular invoice, draft, and an insurance policy. The letter of credit also contains an expiration date. Before payment, the bank responsible for making payment, verifies that all document conform to the letter of credit requirements. If not, the discrepancy must be resolved before payment can be made and before the expiration date.

A letter of credit issued by a foreign bank is sometimes confirmed by a U.S. bank. This confirmation means that the U.S. bank (the confirming bank), adds its promise to pay to that of the foreign bank (the issuing bank). If a letters of credit is not confirmed, it is advised through a U.S. bank and thus called an advised letter of credit. U.S. exporters may wish to confirm letters of credit issued by foreign banks if they are unfamiliar with the foreign banks or concerned about the political or economic risk associated with the country in which the bank is located. An Export Assistance Center or international banker can assist exporters in evaluating the risks to determine what might be appropriate for specific export transactions.

A letter of credit may either be irrevocable and thus, unable to be changed unless both parties agree; or revocable where either party may unilaterally make changes. A revocable letter of credit is inadvisable as it carries many risks for the exporter.

A change made to a letter of credit after it has been issued is called an amendment. Banks also charge fees for this service. It should be specified in the amendment if the exporter or the buyer will pay these charges. Every effort should be made to get the letter of credit right the first time since these changes can be time-consuming and expensive.

To expedite the receipt of funds, wire transfers may be used. Exporters should consult with their international bankers about bank charges for such services.