If you're just beginning your professional career, you might be confused by the different application materials that are required from you. For most jobs, you'll need a resumé and a cover letter to apply. By understanding the different functions of these two documents, you'll be able to bring them together in a stronger, more cohesive application.
Bullet Points v. Paragraphs
Your resumé is an overview of all your past experiences and your skill set neatly summarized in a list format. Your cover letter, on the other hand, gives you the opportunity to explain one or two specific past experiences more thoroughly in order to demonstrate clearly to potential employers why you would be a good fit for the role. Thus, your cover letter requires more lengthy explanations and details, so it's formatted in paragraph style.
Quick Edits v. Major Rewrites
Your resumé should be tailored to each job you apply to based on the skills necessary for the position. Place the most important experience for the role at the top of your resumé and edit your descriptions under each job title to make them as relevant as possible for the position. These resumé changes can be made relatively quickly, but each cover letter for each job application requires much more time. Indeed, your cover letter for each application has to be highly specific to that particular job to demonstrate effectively why you want that job and why you would be good at it. If you could replace the job title in your cover letter, leave everything else the same, and send it off to another employer and it would still make sense, chances are you're not going to land that job.
Who to Ask For Help
A good resumé showcases your previous experiences and proves to employers that you will help them make their businesses successful. To make a strong resumé, you'll need to understand what employers want to see in potential employees. Thus, if you need help with your resumé, it's best to ask an advisor in your school's Counseling or Career Services center. Career advisors can also help you with your cover letter, but a good cover letter requires strong sentence structure, grammar, and spelling. Don't hesitate to ask your English teacher or professor to look over your cover letter, because they'll know how to best improve your writing.