How to write the title of a letter format

1, the topic of the letter can be written or not. When there is no clear requirement, generally do not write the topic. If explicitly requested, it can be written as "a letter to XX".

2. Letter is an applied style and a widely used communication tool. There are clear and specific purposes and recipients, and there are fixed or customary formats. It is widely used in people's daily life and work. There are two kinds of ordinary letters: ordinary letters and special letters.

3. The format of letter writing

4, the beginning of the title: the top case, and some can also add some qualifications and modifiers, such as dear.