In this bachelor's thesis, the goal is to redesign the WhatsApp mobile application. As is well known, WhatsApp is among the leading mobile applications. As for the design itself, the application is made very well, but I think it would be desirable to upgrade it with features like sending images, changing the background, etc. Since WhatsApp is owned by Facebook, the goal is to make as many similarities and features as Messenger. For example, it would be possible to share text and voice messages and videos from WhatsApp to another application such as Messenger. Posts on Facebook and Viber could also be shared. Personalized conversations would include the ability to change background and conversation colors (text bubbles) when communicating with a specific person, and to change a person's profile picture. In order to find out what people think about the ideas mentioned above, research was conducted in such a way that the respondents were given sketches of what the redesign should look like. After the goal of the research was explained to them, the respondents answered whether they liked the ideas or not, using the sketches. In addition to all of the above, respondents were also offered the opportunity to give their own suggestions and ideas. The program to be used in this bachelor's thesis is Figma.