A resume is a document that most employers require when hiring for a position. It is typically one page long, and it describes your experience and education relevant to the position for which you're applying. A resume is often accompanied by a cover letter.
Having a great resume is one of the most important deciding factors on whether or not you'll be offered a job. It's said that most recruiters spend less than 30 seconds looking at an applicant's resume before they either keep it or toss it, so it's incredibly important to have a visually appealing, well-organized, and easy-to-understand resume that highlights your strengths and sets you apart from other applicants.
A cover letter is used to introduce an applicant to a potential employer. It usually accompanies a resume or CV, and it highlights key skills, knowledge, and experience that would be attractive to an employer. Although there is not a standard layout for a cover letter, it most often includes a header, introductory paragraph, body, and closing.
Cover letters can be a great asset to an applicant, because they give the applicant a chance to introduce themselves in a personal way before an interview takes place. A good cover letter expresses individuality towards a specific position, more so than would a resume, so it's important to research the potential company and job before writing one.