A cover letter is your way of communicating what your achievements are. It is not typically just the front part of your resume; rather, it is much more than that. When you apply for any job, you try to give your best through your resume to find you the right fit for the job. Thus, how you prepare it is very much vital in determining your selection for the job.
Your cover letter must not be a long summary; rather, it should contain points that highlight your achievements from the past and show how capable you are of handling the job. This should be made formally when you go for any job, no matter how big or small. While drafting your cover letter, you should be very clear in your approach.
You should write the cover letter properly because it is the first thing that the employer notices about you apart from your body language. If you succeed in writing a commendable cover letter, the employer will then have the urge to look at the resume, and then they might go through the entire resume if they find the first few points impressive. So, it is an important aspect in determining your success or failure.
