You may be wondering if you need a cover letter. The answer is "Yes!" whenever it's requested or optional. Cover letters are a very important part of "getting in the door". In many instances, it's how you make your first impression and show your interest in the position/company.
How to write a cover letter
Remember with cover letters there is no "one size fits all" as every letter should be tailored towards the employer and the position.
Explain why you are sending a resume
Don't send a resume without a cover letter. Don't make the reader guess what you are asking for; be specific: Do you want a summer internship opportunity, or a permanent position after graduation; are you inquiring about future employment possibilities?
Tell specifically how you learned about the position or the organization
A posting on Handshake, their website, a recruiter you met at a career fair, or a family friend who works at the organization. It is appropriate to mention the name of someone who suggested that you apply.
Convince the reader to look at your resume
The cover letter may be seen first. Therefore, it must be very well written and targeted to that employer.
Call attention to elements of your background
Education, leadership, experience - that are relevant to a position you are seeking. Be as specific as possible, using examples.
Reflect your attitude
Personality, motivation, enthusiasm, and communication skills can be demonstrated through your letter.
Provide or refer to any information specifically requested
If they ask you to address a specific question in your cover letter be sure to include that as well as anything else that might not be covered in your resume, such as availability date, or reference to an attached writing sample.
Indicate what you will do to follow-up
In a letter of inquiry, ask about the possibility of an opening - don't assume the employer will contact you. You should say something like, "I will contact you in two weeks to learn more about upcoming employment opportunities with [name of organization]." Then mark your calendar to make the call.