If you use your iMac and an ipad at the same time the iMacs mouse appears on the ipad if you position it extreme left, so then you can use the mouse on your ipad just like on the iMac , but you can also just drag and drop files from one to the other without using airdrop method, this is very fast and convenient , i only stumbled on it by mistake, perhaps I'm a bit behind times but just incase you didn't know about this, its a big big win for users, we are actually getting things we should have had years ago. i assume it might also work on iPhone 11 max pro, will test it later.
Hope this helps someone.