If I want a client to listen to the song, can I submit an image of their ear so they get the best sound possible or how does that work?

The best solution would be to create a new trial account for your client. They can then submit the image of their ear and experience the best sound possible. You can add or remove any existing users by clicking on "+" or "-" on the user profile. We are working on newer versions of the plugin, where you will have the option to send invites to the new users from inside the plugin. It's coming soon, so stay tuned!

Related Article:

How do I add a new user profile or remove an existing user profile?

How many user profiles can I have and do they each have up to 5 for the custom ear images?