EmailsField is a form field for entering more email addresses.
Just use the Composer:
cd path/to/your/atk14/project/
composer require atk14/emails-field
ln -s ../../vendor/atk14/emails-field/src/app/fields/emails_field.php app/fields/emails_field.php
composer update --dev
cd test
../vendor/bin/run_unit_tests
EmailsField is free software distributed under the terms of the MIT license