An attachment letter ?

An attachment letter is a formal document that is sent along with a resume or job application to provide additional information about the applicant's qualifications and experience. It is used to highlight specific skills, experiences, or achievements that are relevant to the job being applied for. The attachment letter should be concise, well-written, and tailored to the specific job or company. It is important to make a strong case for why the applicant is the best candidate for the position.