Summary: it may be a long time for you to write such a formal letter. As you may not familiar with the form of job application letter, here I provide you the five parts of it and things you should pay attention to.
Usually, Job application letter includes title, body, ending, signature and time, and enclosure. A job applier should pay attention to every part of the job application letter as it may decide that whether you can gain the interview chance or not.
1. Title
If you know well that who you are writing to, then write his/her name in title. Use Mr/Ms before the name if you have no idea about the gender. And if you know nothing about the letter receiver, try Dear Manager.
2. Body
It's no doubt the most important part for a job application letter. Remember to give a good sequence of all information you provide.
3. Ending
It's quite easy for this part. Give a short sentence to make a sincere wish. "Best wishes" and "Have a nice day" are both good choices.
4. Signature and time
If you send email for job application, what you should do is just typing your name and time. However, for ordinary mail, you should give hand written signature to show respect.
5. Enclosures
If there are documents that you intend to enclose with the letter, firstly you should give a clue at the end of the letter, and the clue should also include the general information of the enclosures. One thing you should bear in mind that you should only enclose materials that are important and may do good to your job gaining.