How to transfer ring tone from mac to iPhone?

Hi all, trying to transfer ringtones made in garage band to iphone. I am using a mid 2011 imac with intel core i5 to an iPhone 8 plus. I have updated both ios's to 10.13.2 and 11.2.2. Using the apple suggested method of copy and paste does not work. I tried different versions (keyboard shortcuts, drop down, 'paste' in the Tones window, all have not worked. Any other work arounds?

THANK YOU!