Think of a resume as “self-advertisement” that sums up your experience on one page. Your resume is one of the most important pieces of your job application. It gives the hiring manager an overview of the qualifications you have for the job for which you’re applying. You should also familiarize yourself with the difference between a resume and a cover letter.
Your resume is arguable the single most important part of the application process. A well-organized, relevant resume will set you up to get an interview, while a poor resume will get completely lost in the sea of applicants. This is a fairly modern concern, as job postings now get thousands of online applications a day.