The global pandemic accelerated the shift to remote teaching, leading to a rise in digital course materials such as textbooks. However, existing literature indicates limited research on how online students utilize digital textbooks and the features they find valuable for their online learning experiences and desire to aid their learning. Therefore, this research aimed to explore the experiences and perceptions among diverse online students and then draw implications for designing future intelligent textbooks. This study surveyed online degree-seeking students (n = 1236) from three different institutions in the United States in 2022. Based on the mixed-method research design, this exploratory study used qualitative data from open-ended questions and quantitative data from closed-ended questions to theme response patterns. The results indicated that most participants had used at least one digital textbook, and in general, they were familiar with such features as searching, visuals, and embedded assessments. These features, associated with self-directed and multimedia learning, received more positive ratings than adaptive or personalized learning features such as chatbots and recommended content. In the study's findings, surveyed participants described future intelligent digital textbooks as ideal for self-directed learning since they can accommodate diverse learning needs and are flexible and affordable. This study provides insights into future intelligent textbooks and other digital materials as a comprehensive learning system. It supports their use for empowering online learners to go beyond text-based learning and enhance their digital learning experience.