Yes, without a good cover letter, your chances of getting a job drastically decrease. In a professional cover letter, you will get to elaborate on your qualifications and accomplishments and explain why you would be the best person for the job description. Remember that you should write a new, personalized cover letter for each job position you are applying for since companies check for specific keywords.
Your cover letter should never be more than one page long because the recruiter won’t spend a lot of time on it. Ideally, stick to 3/4 of a page cover letter format. Divide your letter into three sections, where each of them can be read in 10 seconds or less. Using a cover letter builder or reading a mechanical engineer cover letter sample can help you better understand what your letter should look like.
If you haven’t worked before or do not have a lot of experience in your field, you can still write a compelling resume. Instead of your work achievements, mention your academic background, internship projects, or volunteer work where you demonstrate the skills needed for the job.