After the fourth paragraph leave a blank space, same as you should do in the beginning, after the salutation (Dear).Write the proper closing, as described above and your name.
You should spell the name of the month and use four digits for the year.
You can put in front of the date the location, like Sofia, 2nd December 2000.
For academic purposes, the document used is typically called statement of purpose, and is laid out after somewhat different rules.
The CL is short (200-250 words), with a quite rigid structure and has the layout of a letter.
Its goal is to introduce the CV, to bring to attention aspects of your activity that can help your application and are not listed or not presented in the proper light in the CV. The layout is that of a formal business letter: your address and contact details come under your name, in the upper right corner of the page.
In short, its goal is to answer the recruiter's question: "Why should I hire this person? Underneath, aligned left, write the name, function, organisation and address of the person you are writing to.
If you do not know the name, start with Dear Sirs, or Dear Sir or Madam and close with Yours faithfully.
In American business correspondence, Yours truly is acceptable in both cases.
Do not start the body of the mail with a capital letter, since it follows a comma. Ideally, a cover letter has no more than four paragraphs.
The goal of the first is to specify what you are applying for and how did you find out about that opportunity.