Who prepares the Guidelines?

The Brand guideline should be prepared by whoever developed the brand. Depending on the size of the Organisation, Often, Brand agencies are responsible for developing the different elements of a brand, especially after rebranding and they are responsible for developing the guidelines for the Organisation that employed them. Landor who developed the BP brand and Wolff Olins who developed the London 2012 Olympics logo will be responsible for the brand guidelines. It should be part of the project’s deliverables.
For smaller brands or startup, the graphics designer who developed the brand identities should make the guidelines available. Artist Simon Oxley designed the now-famous Twitter bird logo which was Twitter bought on iStockphoto for $15, then Twitter was an upcoming start-up company but the bird has been redesigned, the new design is presented under their brand resources on their website .
If the business owner or the company has developed the brand identity, it is essential to document the creative decisions they have made. Microsoft changes its logo for the first time in 25 years; the logo developed mainly by Microsoft employees. That is an in-house design, and they must prepare their identity guideline as they expect various stakeholders around the world knows about the new brand and how it should and should not be used.