Corporate identity is formed from four components. It is naive to believe that a simple description of the company and a beautiful design of the brand book bring some benefit to the brand: it will bring customers, improve the status in the market - no, without taking into account the position of the buyer, you will not gain benefits.
Creating a brand book can be based on different models. The most common is the 4D model, which takes into account four components at once: functional - the real benefit and benefit (what I will get by buying or ordering); psychological - how I will feel when ordering a product or service; social - what status will I acquire; spiritual - how will I feel after the acquisition? I will become more experienced or acquire skills.
If you have a large company and don't have a brand book, it's time to think about its development, as its absence is fraught with a number of difficulties. For example, designers not focused on the brand book may not guess what target audience your banner is designed for or use the wrong shade or color at all, which can quickly reduce brand awareness.
Every company should understand that a brand book is a necessity, it is your style, and also a reference point for everyone who cooperates with you.
