This is very simple. It's called a 'cover letter'. It has 5 primary parts:
1. Name and age (birthdate).
2. Where you were born and where you live currently.
3. Your educational background, and your current occupation (in detail).
4. A little about your family situation (married or single, living with parents, etc.)
5. Your hobbies or interests, clubs, organizations, etc.
If it's sent by e-mail should also include an attached current photo. If you are sending to a foriegn county, you should also include a scanned copy of your passport.
It shouldn't be too 'wordy' but it needs to be accurate and interesting to read at the same time. It shouldn't be any longer than one page.
Good luck! :)