A content style guide is a crucial document that outlines the editorial guidelines for tone, structure, voice, and values of a brand. It contains essential information such as company details, audience information like demographics and pain points, grammar guidelines, word usage rules, formatting information, external and technical style guides, competitor information, channel-specific guidelines, media, SEO, and hashtag guidelines, best-performing content examples, resources to learn more about the company, and how to help your company implement the style guide. A well-crafted style guide can help create a consistent brand impression, improve content quality, and increase efficiency among employees and contractors. While it's not necessary for all companies, most benefit from having one, especially those with large teams or multiple channels of communication. The document should be regularly updated to reflect changes in messaging, product UI, and branding transformations.