The reading function of the iPhone can be set up through the following steps: 1. Open the iPhone's "settings" application. 2. Choose the 'General' option. 3 Scroll to the bottom of the screen to find the "Ancestors" option. 4. Choose the voice option. 5. Press the "Read" button to select the content to be read and press the "OK" button. With this, the reading function of the iPhone was successfully set up. The user can read the selected content aloud when needed.