Aditional Field in API

1

How i fill or retrive Aditional Field with API ?

2

Get, by default you will receive it.

fill:

$ApiUrlCust = "admin/customers/customer"; 
        $arr = [
            'additional_attributes' => [
                'field_name' => 'value'
            ]
        ];
$result = $api->api_call_put($ApiUrlCust, $customer_id, $arr);
3

Thanks this work for me