All resumes you submit during your job search require a cover letter. A cover letter complements your resume, but doesn't duplicate it. It's a way to give your resume a more personal feel and explain relevant experience to the interviewer. It also gives the hiring manager a sample of your writing. Cover letters should be personal and tailored specifically to the position and company you're applying for, including who you address the letter to. You must improvise if you don't know the name of a specific person to whom to address the letter.
Look on the company's website for the name of the hiring or personnel manager. Call the company and ask the secretary for the name of the personnel director if you have no luck with the website.
Address the letter to a gender-neutral term for the person in charge of hiring, such as hiring manager, human resources director or personnel manager.
Put something specific to the job, such as "Re: Accountant Manager" for an accountant manager position, instead of a salutation.
Write your cover letter in a basic font and use 1-inch margins around the entire page. Limit yourself to writing one page.