In a nutshell, a personal letter is written from an individual to an individual, while a personal business letter may be written by an individual to a business. Consumers, supporters or everyday folks often reach out to businesses to express interest in a service, concerns about a product, satisfaction or dissatisfaction with the company or for any number of appropriate reasons. These letters should follow a formal-letter style. Why? For one reason, the businessperson to whom you address your letter will take it more seriously if it is written at least somewhat formally, and it's just plain old good manners to address a businessperson in a more official fashion.
Tip
A personal business letter is written by an individual to a business.
