House style refers to maintaining consistency in a company's branding elements such as its logo, graphics, colors, fonts, and positioning across all business documents, marketing materials, and products to create a recognizable brand and corporate image. The document provides Tesco as an example, outlining how it uses consistent branding with its blue, red, and white colors and "Every little helps" slogan across its website, stores, products, leaflets, and documents to be easily recognized by customers. It advises developing a simple logo and sticking to the same fonts and colors across documents to establish a clear house style for a business.