The starter motor powers the engine to "turn over" and start when the driver turns the ignition switch and it enables the driver to restart the engine once it has been switched off. If the dirver turns the ignition to the start position and only a "click" can be heard, it may be a sign of a low battery, a loose battery connection, or a failed starter solenoid. If it turns out that the starter has failed, then a starter motor replacement is needed.
When replacing the starter, the technician has to disconnect the battery and remove the electrical wiring and hardware securing the starter. The failed starter is removed and the new one is installed.
Most manufacturer factory warranties will cover the cost of a starter motor replacement under their bumper-to-bumper warranty. After the factory bumper-to-bumper warranty expires, an extended auto warranty is an option that will give you extended coverage if the starter motor fails in your vehicle.