A reference letter is a written document that provides a recommendation for an individual, often used in job applications or academic admissions. It typically highlights the person's skills, experiences, and character traits, helping potential employers or institutions assess their suitability for a position or program. These letters are usually written by someone who knows the individual well, such as a former employer, teacher, or mentor. A strong reference letter can significantly enhance a candidate's chances of success by offering credible insights into their abilities and work ethic, making it an important part of the application process.