To perform a soft reset on an iPhone, follow the steps below:
1. Press and hold the 'Sleep/Wake' button (located on the top or right side of the phone) and the 'Volume Down' button (located on the left side of the phone) simultaneously.
2. Keep holding both buttons down until the screen goes black and the Apple logo appears.
3. Release both buttons and wait for the phone to restart.
Performing a soft reset on your iPhone can solve minor software issues, and it is recommended to do so if your phone is acting slow or unresponsive. However, if your phone continues to have problems, you may need to seek further technical assistance from an authorized Apple service provider or Apple support team.