What is the purpose of a cover letter?

When you send your resume to a company do you use a cover letter? The answer should be yes and most people do send one. You probably have a good idea why you send one, its an introduction, right? Or does the cover letter have a different purpose?

The main purposes of a cover letter are:

1. An introduction to your future employer, which will be the first bit of information that they have about you.  
2. It sums up why you want this particular job, cover letters shouldn’t be a form letter that you just change the names and mailing addresses. You need to personalize each and every one. 
3. You will tell the employer a little bit about yourself without repeating what is on the resume. 
4. You will also show the employer what you can provide the company if you are hired. 
5. Indirectly, and this is very important, your writing will show your communication skills and your ability to convey your personal story in a one page letter. Make sure that your spelling and grammar is perfect!