The application design of entertainment and learning content for children has been a growing sector since the tablets and app stores become popular. There are dozens of new applications being added in app stores every day, but few of them can offer children a meaningful fun or learning through fun experience. The graphical user interface, which is the visual layer where all the interaction between the child and the game takes place, is one of the most important factors in the effectiveness of the games in question. When the literature in this area is examined, it is observed that the importance of graphical user interface design has been overlooked in terms of usability in applications. By using the descriptive research method, this article examines how a graphical user interface design can enrich the usability and entertainment, which will enable the use of games and games with learning contents for children. In this respect, a general framework is drawn about the elements of age-appropriate design, visual representation, colors and typography, which provides the entertainment and usability in children-oriented applications. These elements are examined with examples from the target age group and suggestions are made.