At the end you should sign off with "sincerely yours" or any other related salutation. If you are writing a letter of intent for graduate school then it would have a different content. First of all letter of intent would start with your name, address, contact number and email address. After you have mentioned the date, you should then add a salutation like "Dear Sir/Mam".
Many newcomers to the world of international business are given confusing advice on the proper documents to use in their business. The Letter of intent / LOI is a document that many refer to, but actually is poorly understood. Without proper understanding of the document you might find yourself making mistakes in your business that will cause you great embarrassment.