A social-business letter should be concise and should adequately express what you want to express without dragging on. In the first paragraph, state your purpose in writing the letter.

According to Purdue's Online Writing Lab, or OWL, the main parts of a business letter include a return address, date, recipient's address, formal salutation, body, closing and signature.

However, when writing the closing paragraph of your cover letter, it’s easy to have a passive voice because you don’t want to appear overconfident.

An article on using the correct format when writing a formal letter.

On the other, he’s done so by dropping one of the wildest closing paragraphs in resignation-letter history. Strap in tight, people. This is one hell of a rollercoaster.