After you have written down the date, you can move on to the body paragraph that contains your intention to apply for job. Things you would state include your objective of joining the company? How can you enhance company's productivity? What is your previous experience in the field you are applying for? What is your academic background and how it can help you in your job? Lastly you can list down basic skills and experiences that you have attained from previous jobs, if any.
It really could not get more simple than this, but all too many people insist on confusing themselves on this point by listening to bad advice peddled by people who supposedly have closed this deal or that deal or 50 deals on their word.