A cover letter is a one-page document that you submit as part of your job application. It should include your contact information, a greeting, an opening paragraph that grabs the reader's attention, a body that highlights your qualifications and motivation for the position, and a closing paragraph that includes a call to action. It's important to customize your cover letter for each job application, and to proofread it carefully before sending. Using a tried-and-tested format and following the employer's instructions are also crucial. For more details, you can refer to the search results.