title: Save and display specific payment gateway additional field everywhere in Woocommerce
body: <p>I am using <em>"<a href="https://stackoverflow.com/questions/52164954/additional-field-on-checkout-for-specific-payment-gateway-in-woocommerce/52168021#52168021">Additional field on checkout for specific payment gateway in Woocommerce</a>"</em> answer code, that displays an additional dropdown field for specific payment gateway in checkout page.</p>
  
  <p>How to save and display the options on the orders and on email notifications?</p>