Display custom fields value in the email via shortcode

Hi,

I have added a custom field billing_gender (checkout) and I will want to use the value of the field via a shortcode. In order to place it anywhere in the body of the text.

Ex: {billing_gender} {customer_name}, Thank you for your purchase.

I saw that some plugins give this possibility via hooks :

https://www.cxthemes.com/documentation/email-customizer/shortcodes-email-customizer/

https://wordpress.org/support/topic/display-custom-user-registration-fields-in-the-email/

Thank you for your attention

(Google translate)