Can I apply for a patent for the cover or inside page of this book designed by myself? Is it sold in the store?

Yes, but you can apply for a patent for invention if you have the skills. It is suggested that the types of copyright patents you apply for at the same time have different regulations in different countries. In China's patent law, there are: invention patent, utility model patent and design patent; In Hongkong patent law, there are: standard patent (equivalent to Chinese mainland's invention patent), short-term patent (equivalent to Chinese mainland's utility model patent) and design patent; In some developed countries, it is divided into invention patents and design patents. "The so-called products refer to all kinds of new products that can be manufactured in industry, including solids, liquids and gases with certain shapes and structures. The invention patent does not seek the technical achievements that can be directly applied to industrial production through practice, but it can be a solution to technical problems or an idea with the possibility of industrial application. However, this technical scheme or idea cannot be confused with a simple topic or idea, because a simple topic or idea does not have the possibility of industrial application.