AirDrop is iOS's way to share content between iPhone, iPad and iPod Touch devices. If AirDrop is missing, do as follows to hide / show AirDrop in Control Center on iPhone and other iOS running devices:
1. Open the Settings application from the home screen
2. Go to the General settings and scroll down to the middle
3. Tap to open the Restrictions settings
4. Now, you either need to create a Restrictions Passcode or enter your current passcode for the Restrictions.
5. After entering the Restrictions menu, make sure it is Enabled,
6. If AirDrop is not showing in the Control Center, make sure to toggle On the AirDrop button (If you want to to hide AirDrop in the Control Center, keep the AirDrop button toggled off)