airdrop?

How do I activate Airdrop on my iMac?

I have an iMac12,2 running macOS 10.13.4 and 16GB RAM.

When I go to Finder -> System Preferences -> Extensions -> Share Menu I see this: (oops, a screen snapshot which I seem to be unable to paste here . . . 😟 )

which is a display of Mail, Messages, AirDrop, with their checkboxes checked but greyed out, followed by Reminders and about 20 other items; some checked, some not; some I recognize, some I don't. Only one (Add People) has its checkbox on and greyed out like the three at the top of the list.

Are those that I don't recognize potential security risks? Should I be uninstalling them?

Oh well, All I want to do is move a photo from my iPhone to my Mac so I can edit it. I thought Airdrop would do this for me. I can't get it to work.