In the 6G wireless communication, intelligent reflecting surface (IRS) has emerged as a transformative technology in a new era of intelligent and efficient wireless networks. IRS can manipulate radio waves, which means they can help to improve communication in terms of coverage, capacity, and energy efficiency. IRS can overcome obstacles such as signal blockage, path loss, and interference, improving communication reliability and performance. IRS can adaptively reconfigure the wireless propagation environment according to changing conditions. IRS can adjust its reflective properties dynamically in real time, optimizing signal propagation based on user location and channel conditions. Propagation measurements are essential for understanding signal propagation processes and describing wireless channel behavior. These measurements involve collecting data on signal strength, fading, delay spread, and other channel parameters in various environments. Channel modeling techniques aim to represent wireless channel behavior in mathematical models accurately. These models incorporate factors such as path loss, multipath fading, shadowing, and interference to simulate the propagation of electromagnetic waves in different scenarios. Wireless channels are inherently nonstationary, evolving unpredictably in response to environmental changes. This unpredictability poses a significant challenge for propagation measurements, which aim to characterize the behavior of wireless channels over time and space. Overcoming these challenges requires integrating IRS into 6G wireless communication systems, which promises to make a big difference in performance. Thus, this chapter aims to comprehensively review the propagation measurements and channel modeling techniques in 6G wireless communication via an IRS.