Wearable healthcare sensing devices have become significant in upgrading continuous, real-time health monitoring, offering personalized and cautious healthcare solutions. This chapter mainly scans the key applications of wearable devices, including vital sign monitoring (e.g. heart rate, respiration rate, blood pressure), chronic disease handling (e.g. blood glucose, cardiovascular diseases), and mental health monitoring (e.g. stress and anxiety). The incorporation of advanced sensors, such as capacitive, piezoelectric, and optical sensors, and wearable devices, provides non-invasive, continuous tracking of physiological parameters. Advancements and improvements in materials utilized, including flexible substrates, carbon-based nanomaterials, and self-powered systems, resulted in the enhancement of device comfort, performance, and durability. This chapter emphasizes the potential of wearable biosensors in real-time health monitoring and the transformative impact they have on managing chronic conditions. Furthermore, the role of these devices in addressing mental health issues, such as stress and anxiety, through biomarkers like heart rate variability and cortisol levels, is also discussed. The continuing evolution of these technologies offers promising avenues for improving overall healthcare delivery and outcomes.