The inspiration for miniature, high-quality, lightweight, and intricately linked technologies has come from traditional electric devices made of rigid crystalline semiconductor wafers. A concurrent investigation that progresses quickly for emerging electronics combines functionality and extensibility to produce user-friendly applications. A variety of studies have already been reported on the manufacture of sensors and smart gadgets for stretchable, foldable, and composite materials, such as polyurethane sponge, polyimide, cellulose paper, natural rubber, etc. The nanomaterials are highly suited to producing broadband photodetectors, temperature, pressure, and stress sensor applications in the fields of optoelectronic devices, cameras, drugs, protection, and surveillance. Like consumer electronics, robots, prevention, medical care, security equipment, environmental monitoring, domestic defense, and space travel, modular sensors can also be used as promising components for smart sensing applications. Sensors are typically created with flexible substrates. Wearable smart sensors and technology essentially hold tremendous potential for monitoring a person’s physiological parameters to prevent body malfunctions. This chapter classifies the research according to the materials used to make the device, networking technologies, and various control tasks. Also, throughout the chapter, obstacles for current sensing systems as well as emerging prospects for versatile wearables concerning their market prices are briefly explained.