Branding Manual Guideline
Brand guidelines, also known as a brand style guide, govern the composition, design, and general look-and-feel of a company's branding. Brand guidelines can dictate the content of a logo, blog, website, advertisement, and similar marketing collateral.
These branding rule books help graphic designers, marketers, web developers, community managers, and even product packaging departments all stay on the same page, and present a unified vision of the brand to the public.
Picture the most recognizable brands you can think of. Chances are, you've learned to recognize them because of the consistency across the messaging -- written or visual -- these brands broadcast. The same brand colors are reflected across them. The language sounds familiar. It's all very organized and, while not rigid, it's cohesive.