The purpose of a data model in software applications is to define how data is structured, stored, and accessed within a system. It outlines relationships between different data entities and specifies the formats, constraints, and regulations governing data use. Data models are critical for ensuring data integrity and enabling efficient data retrieval. They can take various forms, including relational, object-oriented, or document-based models, depending on the application requirements. Properly designed data models facilitate seamless integration and improve the overall functionality of software applications.