Sometimes a person's gender is unclear from a name _ names like "Corey" or "Blake," are both common women's and men's names. If that is the case, do some investigating to determine gender from searching on LinkedIn or a company website. But if it remains ambiguous, simply write out the person's full name, dropping the title. For example, "Dear Corey Meyer."
When writing an application letter, remember that you probably have competition. Your audience is a professional who screens and hires job applicants—someone who may look through dozens or even hundreds of other applications on the day she receives yours. The immediate objective of your application letter and accompanying resume is to attract this person’s attention. Your ultimate goal is to obtain an interview. As you write your application letter, be sure you complete three tasks: catch the reader’s attention favorably, convince the reader that you are a qualified candidate for the job, and request an interview.