I am going a bit OT here, so maybe I should start a new topic, but I find that not only can't I do AirDrop from my iPhones to my iMac (apparently because of the model of iMac I have, even though AirDrop is featured in its Finder menu), but I also can't AirDrop from one iPhone to another, even though both are on the same wifi network and both are running the latest version of iOS 11. When I try to transfer a photo for example, I click the 'sharing' icon, and choose AirDrop, which shows a note saying
"Share instantly with people nearby. If they turn on AirDrop from Control Centre on iOS or from Finder on the Mac, you'll see their names here. Just tap to share".
Well, I don't see any names, despite setting AirDrop to "everyone" on both phones. At the very least, this amounts to poor instructions from Apple - I mean, if there are other conditions like sharing location services, they should say so. I'm going back to try it some more and may start a new topic. I realise that AirDrop has NEVER worked for me.