In the digital age, people may not be able to live without smart devices because they easily adopt them. IoT has made smart devices possible, which consist of sensors, connectivity, the cloud, and user interfaces. IoT research places sensors at the forefront of smart devices. IoT sensors are efficiently used in different IoT applications to develop smart environments in all fields. These sensors act like human sensing organs that collect real-time information from physical objects or the environment and convert it into electronic signals for processing in the IoT. Normally, two types of networks are applied in IoT: long-range low-power wide area networks and short-range networks. This review aims to assist researchers in understanding IoT applications and protocol classifications using short-range and long-range wireless technology that can communicate wirelessly within regions that facilitate IoT communication from a minimum distance of one millimeter to a few kilometers. This paper presents the types of sensors and various applications of IoT, as well as the energy requirements of different protocols and applications. Each network type has its own unique characteristics regarding energy consumption in the IoT network.