The most common cause of a clicking noise in this situation is a bad starter. In some cases, the problem might be related to the battery.
For some drivers, the first hint of a bad starter is a clicking noise when trying to start the car. The clicking noise occurs after the key is turned. Slow cranking is another sign of a bad starter. Sometimes, the car may not start at all when the starter motor is bad.
The problem could also be related to a bad battery. One way to determine whether the issue is related to the starter or the battery is to turn on either the headlights or the interior lights. If the lights come on, the problem is more likely to be with the starter than the car's battery.