A logo is one mark. A brand identity is the complete system that makes your business recognizable everywhere. Colors, typography, patterns, voice, photography direction, business cards, social media templates, and a guidelines document that tells any designer exactly how to use it all correctly. The logo is maybe 10% of the system. Businesses that stop at a logo end up with a website that uses different fonts, social media in the wrong shade of blue, and business cards that do not match anything. The system is what keeps everything cohesive.