Q: air drop does not communicate with my i mac to i phone 6 plus

What year is your Mac? Note the following from Use AirDrop to send content from your Mac - Apple Support

To send items to an iPhone, iPad, or iPod touch, you need a 2012 or newer Mac model with OS X Yosemite or later, excluding the Mac Pro (Mid 2012).

If that isn't the issue, there are some other things in the above link that may help.