First, read the English article below.

Include the date the letter was written or finished on the top right of the letter.  Write the date in month-day-year format. Writing the month out in text is usually considered standard format, but you could also get away with writing the entire date in numeric form. The date should be aligned to the right side of the page. The salutation "Dear" is still the most common one to use, but depending on the relationship you have with the recipient, you might be able to write the recipient's name without formalities.  The salutation should be left aligned and followed with a comma. When writing a friend or peer, you can usually write their first name only. For example: "Dear Jane". For even more casual friendly letters, you might be able to replace the "Dear" with a casual greeting like "Hello," "Hi," or "Hey." If writing an elder or someone you should show a little respect to, include a personal title and the last name. Example: "Dear Ms. Roberts" Leave a blank line between the salutation and the main text of the letter. The introduction and conclusion should only consist of a single brief paragraph each, but the body portion is usually significantly longer.  Left-align the main text of the letter but indent the first line of each paragraph. The entire main text should be single-spaced. Usually you do not skip lines in between paragraphs with a friendly letter, but you can do so acceptably if it improves the readability of your letter. Leave a blank line after the final sentence of your main text to separate it from the closing. "Sincerely" is still a fairly common closing, even for friendly letters. If the letter is casual enough, though, you can include a less conventional closing. Try something like "Until next time!" or "Talk to you later!" if writing to a close friend.  Follow the closing with a comma, but do not include a typed version of your name after it. The closing should line up with the heading. Sign your name directly below the closing. Usually, your name is written in cursive rather than print. If... 

Now, please write a short abstract for it in Vietnamese. Abstract:
Viết ngày tháng. Viết một lời chào thân thiện. Viết phần giới thiệu, phần nội dung, và phần kết trong bức thư. Kết thư với một lời chào cuối thư thích hợp. Ký tên của bạn.