What feature distinguishes a business letter from personal correspondence?

What distinguishes a business letter from personal correspondence is the combination of a formal greeting and the inclusion of a letterhead. A formal greeting is a hallmark of business communication, demonstrating professionalism and respect towards the recipient. Common examples include "Dear Mr. Smith" or "To Whom It May Concern." These contrasts with the often more casual greetings used in personal letters.

Additionally, the inclusion of a letterhead is a common practice in business letters. Letterheads typically include the company’s name, logo, and contact information, giving the correspondence an official appearance and reinforcing the identity of the organization. This organizational branding and the formality of the greeting are important in distinguishing business communication from personal correspondence, which may not follow such formalities or include specific branding elements.

Therefore, recognizing both the formal greeting and the presence of a letterhead as key features allows for clear differentiation between business letters and more casual personal letters.