This introduction letter not only personalizes the resume but it also allows you to emphasize, and expand on the relevant skills and qualifications that you possess for the particular position or company you are applying to.
Your resume should ALWAYS have a cover letter.The two most common types of introduction letters are cover letters and broadcast letters. A cover letter is used to respond to a particular job posting, while a broadcast letter is used to introduce yourself to a particular organization that the individual is interested in working with. Cover letters and broadcast letters are quite similar.
In this section we are looking specifically at cover letters, but most of the advice applies to both. One key difference is that broadcast letters should only be written once you have thoroughly researched the organization and have a clear idea of how you can benefit them.
The cover letter has two main goals:
Add a personal touch to your application, giving the reader some insight into you as an individual.
Highlight and explain specific relevant points in your resume.
Answer the question, "Why should you hire me?"
Serve as an example of your written communication style.