Recent advances in digital health and increasing access to mobile health (mHealth) tools have led to more effective self-care. This study aimed to identify the minimum data set (MDS) and the requirements of a smartphone application (app) to support caregivers of children with severe burns. The study was performed in three phases in a burn center in the north of Iran in 2022. In the first phase, a literature review was performed. In the second phase, interviews were conducted with 18 caregivers. The third phase was performed in two stages: first, an initial questionnaire was prepared in which the content validity ratio and content validity index were calculated. The final questionnaire included 71 data elements about the MDS and requirements and open-ended elements. Then, the data elements were surveyed by 25 burn experts using the Delphi technique. The minimum acceptable mean score for each item was 3.75. Out of the 71 elements in the first Delphi round, 51 were accepted. In the second Delphi round, 14 data elements were assessed. The most important elements for the MDS were a family relationship, TBSA, the primary cause of the burn, anatomical location, itch, pain, and infection. User registration, educational materials, caregiver–clinician communication, chat box, and appointment booking were the most highlighted functional requirements. Safe login was the most important element for the nonfunctional requirements. It is recommended that health managers and software designers use these functionalities in designing smartphone apps for caregivers of children with burns.