An application letter is merely another name for a cover letter, the official business letter often included with a job application and/or resume and sent to a prospective employer. Although application letters are generally considered optional components of applying for a job, more and more frequently, employers are singling out those who actually take the time to write an application letter as their top picks. Here are a few components of a typical, successful application letter: Professional Style Application letters are usually, and should always, be in an officer letter style, like block style. These letters should be formatted properly and checked for spelling and grammatical errors. Salutation Although many application letters open with a simple "Sir or Madam:", the more successful application letters are addressed personally to the hiring manager (which often takes some research on the part of the job applicant).