Your logo encapsulates your company and its purpose in a single image.
Instantly recognisable, and adaptable for multiple applications, your logo should be applied consistently, as should your wider visual language – your colour palette, your use of typefaces and your use of imagery, iconography and photography.
All of your channel output via email, web and social should feel as if it's coming from the same place.
Your brand identity also needs to work across all forms of media – from digital to print to video.