A resume is typically sent with a cover letter, which is a document that provides additional information on your skills and experience in letter form. A resume is a concise, often bulleted summary, while a cover letter highlights and expands on certain traits or accomplishments that would be unique or ideal assets for the particular job.
A resume is the representation of your professional self. It is a concise compilation of your educational and professional experience, as well as the skills that make you desirable for the workforce. It is what you use to sell your merit and skills to potential employers.