A cover letter is different from a resume, and it is written specifically for the job application of a certain position. To be targeted, the application letter should generally mention the company name, job title and other information. The cover letter should not be too long, because the recruiter has no time to read it carefully. A cover letter usually has only one page, the main purpose of which is to show the other party that he is interested in a position advertised by the other party, and to state his work experience and experience in a very general way.