The current state of technological progress offers extensive opportunities for the development of urban infrastructure and the construction of Smart Cities, but the city will only become intelligent if it raises the living standards of all citizens in it. The Smart City uses information and communication technologies to improve its functionality and long-term sustainability and to increase the living standards of its citizens. In this context, it is necessary to address the issue of mutual communication between the city and the citizen and its implementation. The aim of the paper is to design a suitable smart solution that would streamline two-way communication between the city and its citizens. This solution is an urban mobile application, which is also a simple and yet sufficiently effective solution for the transformation of cities into Smart Cities. The main benefit is the implementation of research assessing the requirements of the citizens of a particular city for the services and functions that the application should offer. After analysing the results, a specific urban application design was processed using User Interface and User Interface design. The proposal consists of seven consecutive phases. All phases were completed in solving the design and the result can be seen in the resulting interactive prototype, which was finally tested by authors and random users representing all age categories. The results of the prototype usability tests enabled a gradual improvement of the solution, which culminated in the confirmation of its effectiveness.