If long pressing the “Network icon group’ doesn’t help you to fix the issue, then here follow another solution to fix AirDrop not showing up in iOS control center.
- Open the Setting app on your iPhone and go to “General”.
- Go to Restrictions, if asked passcode enter it.
- Look for the AirDrop and make sure that it is toggled to ON position.
- Now close the Settings app and then open control panel, you will now see that AirDrop is visible.
After doing all above settings, you will now no longer will be restricted because the feature is enabled and it will work properly as shown in the screenshot below:

Now go to control panel and Turn ON the AirDrop feature and you can then start sharing files without any issue.
Note: The above-solution will work properly but sometimes the device needs rebooting only to make sure AirDrop works properly.