1. First, we need to turn on the fitness tracking function of the iPhone. Click Settings-Privacy-Exercise and Fitness, and click the button on the right side of Fitness Tracking to open this function.
2. At this point, the iPhone will calculate the user's steps. Next, we need to enter the "Health" application, click the "Body Measurement" option in the "Health Data" tab in the lower left corner, and input our height and weight, so that the iPhone can better estimate the stride size.