Answer:

Formal communication is communication through pre-defined channels set by organizations. They are typically conveyed from top leadership to various departments that funnels down to lower level employees. It is backed by organizational procedure, and it is necessary to fulfill the goals of the organization.

Informal communication is more relational than formal. It is not backed by any pre-determined channels and can happen anywhere within the organization. The primary goal of this messaging is to preserve and establish relationships with colleagues and superiors and subordinates. Since it is not defined by any channels, messaging moves a lot faster, but it is without any paper trail or official documentation