The covid-19 has been forcing the speed of digital transformation in human life, including the health sector. The government of Indonesia developed Peduli Lindungi Apps, an application to control Covid-19. Peduli Lindungi transforms to Citizen Health Apps (Satu Sehat Mobile) after the Pandemic. In developing countries, most health information technologies (HIT) are often total or partial failures or are unsustainable. This study describes the factors related to the usability of Peduli Lindungi Application and predicts the use of Citizen Health Apps (Satu Sehat Mobile) through the decision tree model. The data was collected from March-June 2022 using a questionnaire. This study distributed a questionnaire to 300 patients from three Public hospitals in Semarang City, Central Java, Indonesia. The questionnaire consists of some measurements comprised of the health literacy index (HLS-EU-SQ10-IDN), Digital Health Literacy Competencies for Citizen (DHLC) , and usability. This study developed a model to predict the usability of citizen health app (former Peduli Lindungi Apps) and resulted in 64.7% accuracy of performance classification. The model of this study describes that sequence factors to affect the usability of Citizen health Apps are health literacy level, digital health literacy, education, and gender. The model shows that health literacy level is the first factor related usability Peduli Lindungi, after downloading the application. Respondents with problematics health literacy should have DHLC in the level expert and the higher education to have high usability while respondents with Non-Health Higher education should have independent and expert Digital Health Literacy to have high usability.