A cover letter is a document sent along with your resume to provide additional information on your skills and experience. It serves as a personalized introduction to a potential employer and highlights why you are the ideal candidate for the job. A well-written cover letter can showcase your enthusiasm for the position, explain any gaps in your employment history, and demonstrate your communication skills. It should be tailored to the specific job and company you are applying to, showing that you have done your research and are genuinely interested in the opportunity. Overall, a strong cover letter can set you apart from other applicants and increase your chances of landing an interview.