Clearly communicating a brand's purpose, objectives and how it plans to serve its audience is the first step in branding. Your mission statement will be key in every other aspect of your branding process as well- giving readers an idea of what your business does and who it serves. This statement may shift over time as the company grows and redefines its goals, but should always stay true to those original intentions!
A clear mission statement will help you identify your target audience. Defining a mission statement can act as an elevator pitch when presenting your brand to a new audience, and it can also be used to determine whether the projects you work on align with what is most important for your company goal.
For employees, following the guidelines of this kind of mission statement could make all their decisions easier while they are in communication or working on behalf of the organization. Lastly, presenting this kind of information about yourself would likely prove highly beneficial if you were trying to find partners or investors because they would see how much value there is in partnering up with someone who has such strong values and goals that tie back into their own business plans as well!