The autoplay icon on an iPhone can be found in the Control Center. To access the Control Center, swipe down from the top right corner of the screen on iPhone X and newer models, or swipe up from the bottom of the screen on iPhone 8 and older models. Once in the Control Center, the autoplay icon can be found under the media controls. It resembles a rectangular box with three curved lines inside. Tapping on the icon will enable or disable autoplay for media content such as videos and music. It is worth noting that autoplay settings may vary depending on the app in use.