Add “Cardholder Name” to WooCommerce Checkout

On WooCommerce checkout I need to add a field “Cardholder Name” and I cannot find where to do this. I use Paypal by Braintree as payment gateway, and in their transaction list the “Customer” field is empty for all entries. According to their tech support, WooCommerce is not transmitting this information to them, since there is no “Cardholder Name” in the WC checkout. This makes my bookkeeping a nightmare. Any advice/help on how to add the “Cardholder Name” to the checkout would be immensely appreciated.
Thank you, Mimi