How would you add a standard custom field to the order page in WooCommerce? You would basically do the same thing. Use the ACF field name as the name of the custom field. Only hitch might be if it is a field like a multiple select, checkbox or maybe a repeater.
How would you set a standard custom field’s value in a plugin action? Again, basically the same with ACF except that you also need to set a special custom field to tell ACF how the value is used. The special custom field name is equal to '_'.$field_name and the value of this field is the ACF field key.
