In the first paragraph, you need to tell the recipient why you are writing a letter to him. If you want to express several thoughts in your email, then start writing each of them with a new paragraph.
Proper formatting of the letter is a guarantee that it will be read carefully and your thoughts will be correctly understood. Use formatting to make your email more readable and easier to read. This is especially important to consider when you are writing long formal letters. A solid canvas of text runs the risk of being sent to the trash immediately after opening.