Communication is everything in the field of business and management. Actually, communication is everything in every field. However, not all communication should be used for the same purpose.
Communication meant to provide data, or information needed to accomplish the goals of the organization, is done formally and following a proper protocol, a chain of command (or directive), and using a specific format. This information is known as "formal" organizational communication.
Formal communication is very important because its uniformity in style and purpose allows for zero subjectivity and 100% engagement with the most important aspects of the business. All information remains on topic, and the result will be more accuracy in productivity.
An example of formal communication is the announcement of someone getting a promotion. What often happens is that someone over at human resources will send the information concerning this promotion in a memorandum format. This is because the importance of this information is not that "so and so got a raise"...but that Mr. X is now the person in charge of department Y in the organization.
Then we have informal communication.
When things that are off the business topic are to be discussed, employees can use informal communication in the form of flyers, newsletters, e-mails, texts or padlock notes (when collaborating remotely). The information contained in these formats should be as light in nature as its delivery. Let's go back to the case of the employee that got promoted. While the formal communication announced the promotion through the perspective of how it affects the organization, the INFORMAL communication will actually look into the more personable aspect of the news.
With informal communication, employees can plan a party for the employee, send their congratulations via e-cards, or express themselves about anything else in a non-binding and personal way. Keep in mind that all information that is written down is still documentation, whether formal or informal. Therefore, therefore, anything that will be read by others must still abide by the quality and performance standards as stated by the organization's mission and vision.